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a(n) has generating function 1/((1-x)^k*(1-x^2)^(k*(k-1)/2)) for k=5.
(history; published version)
#21 by Alois P. Heinz at Thu Apr 16 18:45:13 EDT 2020
STATUS

editing

approved

#20 by Alois P. Heinz at Thu Apr 16 18:35:40 EDT 2020
COMMENTS

a(n,-1,k) is conjectured to also be the count of monomials (or terms) in the Schur polynomials of k variables and degree n, summed over all partitions of n in at most k parts (zero-padded to length k).

STATUS

proposed

editing

Discussion
Thu Apr 16
18:36
Alois P. Heinz: at least it is consistent with the example now.
#19 by Michel Marcus at Thu Apr 16 16:13:42 EDT 2020
STATUS

editing

proposed

#18 by Sean A. Irvine at Wed Apr 15 21:45:28 EDT 2020
EXAMPLE

a(3)=85 since the Schur polynomial of 5 variables and degree 4 starts of off as x[1]*x[2]*x[3]*x[4] + x[1]*x[2]*x[3]*x[5] + ... + x[4]*x[5]^3 + x[5]^4. The exponents collect to the padded partitions of 4 as 5*p(1) + 40*p(2) + 30*p(3) + 150*p(4) + 50*p(5) where p(1) is the lexicographically first padded partition of 4: {4,0,0,0}, a coded form of monomials x[i]^4, and p(5) stands for {1,1,1,1}, coding x[i]x[j]x[k]x[l] with all indices different.

STATUS

proposed

editing

Discussion
Wed Apr 15
21:46
Sean A. Irvine: Don't know enough to answer, but looks like a(n-1,k) would fix the comment.
Thu Apr 16
16:13
Michel Marcus: Alois, do you see ?
#17 by Michel Marcus at Tue Mar 31 11:03:07 EDT 2020
STATUS

editing

proposed

#16 by Michel Marcus at Tue Mar 31 11:01:23 EDT 2020
EXAMPLE

a(n3)=85 since the Schur polynomial of 5 variables and degree 4 starts of as x[1]*x[2]*x[3]*x[4] + x[1]*x[2]*x[3]*x[5] + ... + x[4]*x[5]^3 + x[5]^4. The exponents collect to the padded partitions of 4 as 5*p(1) + 40*p(2) + 30*p(3) + 150*p(4) + 50*p(5) where p(1) is the lexicographically first padded partition of 4: {4,0,0,0}, a coded form of monomials x[i]^4, and p(5) stands for {1,1,1,1}, coding x[i]x[j]x[k]x[l] with all indices different.

STATUS

approved

editing

Discussion
Tue Mar 31
11:03
Michel Marcus: 85 is a(3)  but degree 4 ?  so comment should say degree n+1 ???
#15 by Alois P. Heinz at Wed Feb 08 19:11:03 EST 2017
STATUS

editing

approved

#14 by Alois P. Heinz at Wed Feb 08 19:10:56 EST 2017
LINKS

Wikipedia, <a href="httphttps://en.wikipedia.org/wiki/Schur_polynomial">Schur Polynomial</a>

KEYWORD

nonn,easy

STATUS

approved

editing

#13 by Jon E. Schoenfield at Wed Aug 12 00:05:55 EDT 2015
STATUS

editing

approved

#12 by Jon E. Schoenfield at Wed Aug 12 00:05:53 EDT 2015
EXAMPLE

a(n)=85 since the Schur polynomial of 5 variables and degree 4 starts of as x[1]*x[2]*x[3]*x[4] + x[1]*x[2]*x[3]*x[5] + ... + x[4]*x[5]^3 + x[5]^4. The exponents collect to the padded partitions of 4 as 5*p(1) + 40*p(2) + 30*p(3) + 150*p(4) + 50*p(5) where p(1) is the lexicographically- first padded partition of 4: {4,0,0,0}, a coded form of monomials x[i]^4, and p(5) stands for {1,1,1,1}, coding x[i]x[j]x[k]x[l] with all indices different.

STATUS

approved

editing