OFFSET
1,8
COMMENTS
Column k is Dirichlet convolution of mu(n) with k^(n-1). The coefficients of the polynomial of row n are given by the n-th row of triangle A054525; for example row 4 has polynomial -k+k^3.
LINKS
FORMULA
EXAMPLE
T(4,2)=6, because 6 words of length 4 over 2-letter alphabet {a,b} are primitive and earlier than others derived by cyclic shifts of the alphabet: aaab, aaba, aabb, abaa, abba, abbb; note that aaaa and abab are not primitive and words beginning with b can be derived by shifts of the alphabet from words in the list; secondly note that the words in the list need not be Lyndon words, for example aaba can be derived from aaab by a cyclic rotation of the positions.
Table begins:
1, 1, 1, 1, 1, 1, 1, 1, ...
0, 1, 2, 3, 4, 5, 6, 7, ...
0, 3, 8, 15, 24, 35, 48, 63, ...
0, 6, 24, 60, 120, 210, 336, 504, ...
0, 15, 80, 255, 624, 1295, 2400, 4095, ...
0, 27, 232, 1005, 3096, 7735, 16752, 32697, ...
0, 63, 728, 4095, 15624, 46655, 117648, 262143, ...
0, 120, 2160, 16320, 78000, 279720, 823200, 2096640, ...
MAPLE
with(numtheory):
f1:= proc(n) option remember;
unapply(k^(n-1)-add(f1(d)(k), d=divisors(n)minus{n}), k)
end;
T:= (n, k)-> f1(n)(k);
seq(seq(T(n, 1+d-n), n=1..d), d=1..12);
MATHEMATICA
t[n_, k_] := Sum[k^(d-1)*MoebiusMu[n/d], {d, Divisors[n]}]; Table[t[n-k+1, k], {n, 1, 12}, {k, n, 1, -1}] // Flatten (* Jean-François Alcover, Jan 21 2014, from first formula *)
CROSSREFS
KEYWORD
nonn,tabl
AUTHOR
Alois P. Heinz, Aug 07 2008
STATUS
approved