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A partition product with biggest-part statistic of Stirling_1 type (with parameter k = -2) as well as of Stirling_2 type (with parameter k = -2), (triangle read by rows).
+10
25
1, 1, 2, 1, 6, 6, 1, 24, 24, 24, 1, 80, 180, 120, 120, 1, 330, 1200, 1080, 720, 720, 1, 1302, 7770, 10920, 7560, 5040, 5040, 1, 5936, 57456, 102480, 87360, 60480, 40320, 40320, 1, 26784, 438984, 970704, 1103760, 786240, 544320, 362880, 362880
COMMENTS
Partition product of Product_{j=0..n-1} ((k+1)*j - 1) and n! at k = -2, summed over parts with equal biggest part (Stirling_2 type) as well as partition product of Product_{j=0..n-2} (k-n+j+2) and n! at k = -2 (Stirling_1 type).
It shares this property with the signless Lah numbers.
Underlying partition triangle is A130561. Same partition product with length statistic is A105278. T(n,k) is the number of nilpotent elements in the symmetric inverse semigroup (partial bijections) on [n] having index k. Equivalently, T(n,k) is the number of directed acyclic graphs on n labeled nodes with every node having indegree and outdegree at most one and the longest path containing exactly k nodes. - Geoffrey Critzer, Nov 21 2021
FORMULA
T(n,0) = [n = 0] (Iverson notation) and for n > 0 and 1 <= m <= n.
T(n,m) = Sum_{a} M(a)|f^a| where a = a_1,...,a_n such that
1*a_1 + 2*a_2 + ... + n*a_n = n and max{a_i} = m, M(a) = n!/(a_1!*..*a_n!),
f^a = (f_1/1!)^a_1*..*(f_n/n!)^a_n and f_n = Product_{j=0..n-1} (-j-1)
OR f_n = Product_{j=0..n-2} (j-n) since both have the same absolute value n!.
E.g.f. of column k: exp((x^(k+1)-x)/(x-1))-exp((x^k-x)/(x-1)). - Alois P. Heinz, Oct 10 2015
EXAMPLE
Triangle starts:
1;
1, 2;
1, 6, 6;
1, 24, 24, 24;
1, 80, 180, 120, 120;
1, 330, 1200, 1080, 720, 720;
...
MAPLE
egf:= k-> exp((x^(k+1)-x)/(x-1))-exp((x^k-x)/(x-1)):
T:= (n, k)-> n!*coeff(series(egf(k), x, n+1), x, n):
MATHEMATICA
egf[k_] := Exp[(x^(k+1)-x)/(x-1)] - Exp[(x^k-x)/(x-1)]; T[n_, k_] := n! * SeriesCoefficient[egf[k], {x, 0, n}]; Table[Table[T[n, k], {k, 1, n}], {n, 1, 10}] // Flatten (* Jean-François Alcover, Oct 11 2015, after Alois P. Heinz *)
CROSSREFS
Cf. A157396, A157397, A157398, A157399, A080510, A157401, A157402, A157403, A157404, A157405, A157386, A157385, A157384, A157383, A126074, A157391, A157392, A157393, A157394, A157395.
Triangle read by rows: T(n,k) is the number of permutations of n elements that have the longest cycle length k.
+10
23
1, 1, 1, 1, 3, 2, 1, 9, 8, 6, 1, 25, 40, 30, 24, 1, 75, 200, 180, 144, 120, 1, 231, 980, 1260, 1008, 840, 720, 1, 763, 5152, 8820, 8064, 6720, 5760, 5040, 1, 2619, 28448, 61236, 72576, 60480, 51840, 45360, 40320, 1, 9495, 162080, 461160, 653184, 604800, 518400, 453600, 403200, 362880
COMMENTS
Sum of the n-th row is the number of all permutations of n elements: Sum_{k=1..n, T(n,k)} = n! = A000142(n) We can extend T(n,k)=0, if k<=0 or k>n. Partition product of prod_{j=0..n-2}(k-n+j+2) and n! at k = -1, summed over parts with equal biggest part (see the Luschny link).
Underlying partition triangle is A102189. Same partition product with length statistic is A008275. Diagonal a( A000217(n)) = rising_factorial(1,n-1), A000142(n-1) (n > 0). Let k in {1,2,3,...} index the family of sequences A000012, A000085, A057693, A070945, A070946, A070947, ... respectively. Column k is the k-th sequence minus its immediate predecessor. For example, T(5,3)= A057693(5)- A000085(5). - Geoffrey Critzer, May 23 2009
FORMULA
T(n,1) = 1 T(n,2) = n! * Sum_{k=1..[n/2], (1/(k! * (2!)^k * (n-2k)!)} T(n,k) = n!/k * (1-1/(n-k)-...-1/(k+1)-1/2k), if n/3 < k <= n/2 T(n,k) = n!/k, if n/2 < k <= n T(n,n) = (n-1)! = A000142(n-1) E.g.f. for k-th column: exp(-x^k*LerchPhi(x,1,k))*(exp(x^k/k)-1)/(1-x). - Vladeta Jovovic, Mar 03 2007 T(n,0) = [n = 0] (Iverson notation) and for n > 0 and 1 <= m <= n
T(n,m) = Sum_{a} M(a)|f^a| where a = a_1,..,a_n such that
1*a_1+2*a_2+...+n*a_n = n and max{a_i} = m, M(a) = n!/(a_1!*..*a_n!),
f^a = (f_1/1!)^a_1*..*(f_n/n!)^a_n and f_n = product_{j=0..n-2}(j-n+1). (End)
EXAMPLE
Triangle T(n,k) begins:
1;
1, 1;
1, 3, 2;
1, 9, 8, 6;
1, 25, 40, 30, 24;
1, 75, 200, 180, 144, 120;
1, 231, 980, 1260, 1008, 840, 720;
1, 763, 5152, 8820, 8064, 6720, 5760, 5040;
...
MAPLE
A:= proc(n, k) option remember; `if`(n<0, 0, `if`(n=0, 1,
add(mul(n-i, i=1..j-1)*A(n-j, k), j=1..k)))
end:
T:= (n, k)-> A(n, k) -A(n, k-1):
MATHEMATICA
Table[CoefficientList[ Series[(Exp[x^m/m] - 1) Exp[Sum[x^k/k, {k, 1, m - 1}]], {x, 0, 8}], x]*Table[n!, {n, 0, 8}], {m, 1, 8}] // Transpose // Grid [From Geoffrey Critzer, May 23 2009]
PROG
(Sage)
f = factorial(n)
P = Partitions(n, max_part=k, inner=[k])
return sum(f // p.aut() for p in P)
CROSSREFS
Cf. A157386, A157385, A157384, A157383, A157400, A157391, A157392, A157393, A157394, A157395. - Peter Luschny, Mar 07 2009
A partition product of Stirling_1 type [parameter k = 4] with biggest-part statistic (triangle read by rows).
+10
12
1, 1, 4, 1, 12, 12, 1, 72, 48, 24, 1, 280, 600, 120, 24, 1, 1740, 4560, 1800, 144, 0, 1, 8484, 40740, 21000, 2520, 0, 0, 1, 57232, 390432, 223440, 33600, 0, 0, 0, 1, 328752, 3811248, 2845584, 438480, 0, 0, 0, 0, 1, 2389140
COMMENTS
Partition product of prod_{j=0..n-2}(k-n+j+2) and n! at k = 4,
summed over parts with equal biggest part (see the Luschny link).
Underlying partition triangle is A144878. Same partition product with length statistic is A049424.
FORMULA
T(n,0) = [n = 0] (Iverson notation) and for n > 0 and 1 <= m <= n
T(n,m) = Sum_{a} M(a)|f^a| where a = a_1,..,a_n such that
1*a_1+2*a_2+...+n*a_n = n and max{a_i} = m, M(a) = n!/(a_1!*..*a_n!),
f^a = (f_1/1!)^a_1*..*(f_n/n!)^a_n and f_n = product_{j=0..n-2}(j-n+6).
EXAMPLE
1
1 4
1 12 12
1 72 48 24
1 280 600 120 24
1 1740 4560 1800 144 0
1 8484 40740 21000 2520 0 0
1 57232 390432 223440 33600 0 0 0
1 328752 3811248 2845584 438480 0 0 0 0
1 2389140
A partition product of Stirling_1 type [parameter k = 1] with biggest-part statistic (triangle read by rows).
+10
11
1, 1, 1, 1, 3, 0, 1, 9, 0, 0, 1, 25, 0, 0, 0, 1, 75, 0, 0, 0, 0, 1, 231, 0, 0, 0, 0, 0, 1, 763, 0, 0, 0, 0, 0, 0, 1, 2619, 0, 0, 0, 0, 0, 0, 0, 1, 9495, 0, 0, 0, 0, 0, 0, 0, 0, 1, 35695, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 140151
COMMENTS
Partition product of prod_{j=0..n-2}(k-n+j+2) and n! at k = 1,
summed over parts with equal biggest part (see the Luschny link).
Underlying partition triangle is A144357. Same partition product with length statistic is A049403.
FORMULA
T(n,0) = [n = 0] (Iverson notation) and for n > 0 and 1 <= m <= n
T(n,m) = Sum_{a} M(a)|f^a| where a = a_1,..,a_n such that
1*a_1+2*a_2+...+n*a_n = n and max{a_i} = m, M(a) = n!/(a_1!*..*a_n!),
f^a = (f_1/1!)^a_1*..*(f_n/n!)^a_n and f_n = product_{j=0..n-2}(j-n+3).
A partition product of Stirling_1 type [parameter k = 2] with biggest-part statistic (triangle read by rows).
+10
11
1, 1, 2, 1, 6, 2, 1, 24, 8, 0, 1, 80, 60, 0, 0, 1, 330, 320, 0, 0, 0, 1, 1302, 2030, 0, 0, 0, 0, 1, 5936, 12432, 0, 0, 0, 0, 0, 1, 26784, 81368, 0, 0, 0, 0, 0, 0, 1, 133650, 545120, 0, 0, 0, 0, 0, 0, 0, 1, 669350, 3825690
COMMENTS
Partition product of prod_{j=0..n-2}(k-n+j+2) and n! at k = 2,
summed over parts with equal biggest part (see the Luschny link).
Underlying partition triangle is A144358. Same partition product with length statistic is A049404.
FORMULA
T(n,0) = [n = 0] (Iverson notation) and for n > 0 and 1 <= m <= n
T(n,m) = Sum_{a} M(a)|f^a| where a = a_1,..,a_n such that
1*a_1+2*a_2+...+n*a_n = n and max{a_i} = m, M(a) = n!/(a_1!*..*a_n!),
f^a = (f_1/1!)^a_1*..*(f_n/n!)^a_n and f_n = = product_{j=0..n-2}(j-n+4).
A partition product of Stirling_1 type [parameter k = 3] with biggest-part statistic (triangle read by rows).
+10
11
1, 1, 3, 1, 9, 6, 1, 45, 24, 6, 1, 165, 240, 30, 0, 1, 855, 1560, 360, 0, 0, 1, 3843, 12180, 3360, 0, 0, 0, 1, 21819, 96096, 30660, 0, 0, 0, 0, 1, 114075, 794304, 318276, 0, 0, 0, 0, 0, 1, 703215, 6850080, 3270960, 0, 0, 0, 0, 0, 0, 1, 4125495, 62516520, 35053920, 0, 0
COMMENTS
Partition product prod_{j=0..n-2}(k-n+j+2) and n! at k = 3, summed over parts with equal biggest part (see the Luschny link).
Underlying partition triangle is A144877. Same partition product with length statistic is A049410.
FORMULA
T(n,0) = [n = 0] (Iverson notation) and for n > 0 and 1 <= m <= n
T(n,m) = Sum_{a} M(a)|f^a| where a = a_1,..,a_n such that
1*a_1+2*a_2+...+n*a_n = n and max{a_i} = m, M(a) = n!/(a_1!*..*a_n!),
f^a = (f_1/1!)^a_1*..*(f_n/n!)^a_n and f_n = product_{j=0..n-2}(j-n+5).
A partition product of Stirling_1 type [parameter k = 5] with biggest-part statistic (triangle read by rows).
+10
11
1, 1, 5, 1, 15, 20, 1, 105, 80, 60, 1, 425, 1200, 300, 120, 1, 3075, 10400, 5400, 720, 120, 1, 15855, 102200, 75600, 15120, 840, 0, 1, 123515, 1149120, 907200, 241920, 20160, 0, 0, 1, 757755, 12783680, 13426560, 3719520, 362880
COMMENTS
Partition product of prod_{j=0..n-2}(k-n+j+2) and n! at k = 5,
summed over parts with equal biggest part (see the Luschny link).
Underlying partition triangle is A144879. Same partition product with length statistic is A049411.
FORMULA
T(n,0) = [n = 0] (Iverson notation) and for n > 0 and 1 <= m <= n
T(n,m) = Sum_{a} M(a)|f^a| where a = a_1,..,a_n such that
1*a_1+2*a_2+...+n*a_n = n and max{a_i} = m, M(a) = n!/(a_1!*..*a_n!),
f^a = (f_1/1!)^a_1*..*(f_n/n!)^a_n and f_n = product_{j=0..n-2}(j-n+7).
A partition product of Stirling_1 type [parameter k = -3] with biggest-part statistic (triangle read by rows).
+10
10
1, 1, 3, 1, 9, 12, 1, 45, 48, 60, 1, 165, 480, 300, 360, 1, 855, 3840, 3600, 2160, 2520, 1, 3843, 29400, 46200, 30240, 17640, 20160, 1, 21819, 272832, 520800, 443520, 282240, 161280, 181440
COMMENTS
Partition product of prod_{j=0..n-2}(k-n+j+2) and n! at k = -3,
summed over parts with equal biggest part (see the Luschny link).
Underlying partition triangle is A144353. Same partition product with length statistic is A046089.
FORMULA
T(n,0) = [n = 0] (Iverson notation) and for n > 0 and 1 <= m <= n
T(n,m) = Sum_{a} M(a)|f^a| where a = a_1,..,a_n such that
1*a_1+2*a_2+...+n*a_n = n and max{a_i} = m, M(a) = n!/(a_1!*..*a_n!),
f^a = (f_1/1!)^a_1*..*(f_n/n!)^a_n and f_n = product_{j=0..n-2}(j-n-1).
A partition product of Stirling_1 type [parameter k = -6] with biggest-part statistic (triangle read by rows).
+10
10
1, 1, 6, 1, 18, 42, 1, 144, 168, 336, 1, 600, 2940, 1680, 3024, 1, 4950, 33600, 35280, 18144, 30240, 1, 26586, 336630, 717360, 444528, 211680, 332640, 1, 234528, 4870992, 11313120, 10329984, 5927040, 2661120, 3991680
COMMENTS
Partition product of prod_{j=0..n-2}(k-n+j+2) and n! at k = -6,
summed over parts with equal biggest part (see the Luschny link).
Underlying partition triangle is A144356. Same partition product with length statistic is A049374.
FORMULA
T(n,0) = [n = 0] (Iverson notation) and for n > 0 and 1 <= m <= n
T(n,m) = Sum_{a} M(a)|f^a| where a = a_1,..,a_n such that
1*a_1+2*a_2+...+n*a_n = n and max{a_i} = m, M(a) = n!/(a_1!*..*a_n!),
f^a = (f_1/1!)^a_1*..*(f_n/n!)^a_n and f_n = product_{j=0..n-2}(j-n-4).
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