The On-Line Encyclopedia of Integer Sequences (OEIS)

A374823 revision #4

A374823

Chain-Chain Quilt Numbers: Triangular array of the number of ASM quilts of type C_k x C_n, where C_n is a chain of length n with n+1 elements.

1, 2, 2, 3, 7, 7, 4, 16, 42, 42, 5, 30, 149, 429, 429, 6, 50, 406, 2394, 7436, 7436, 7, 77, 938, 9698, 65910, 218348, 218348, 8, 112, 1932, 31920, 403572, 3096496, 10850216, 10850216, 9, 156, 3654, 90576, 1931325, 29020904, 247587252

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OFFSET

1,2

COMMENTS

These numbers are given by a polynomial in n for fixed k and all n>=k.

For k=n, these numbers count square alternating sign matrices A005130.

REFERENCES

S. Billey and M. Konvalinka. Generalized Rank Functions and Quilts of Alternating Sign Matrices. Preprint.

LINKS

Table of n, a(n) for n=1..43.

CROSSREFS

Cf. A005130, A374819, A374821, A374821, A374822, A374824.

Sequence in context: A002583 A068519 A342848 * A339826 A108041 A259254

Adjacent sequences: A374816 A374817 A374818 * A374825 A374826 A374827

KEYWORD

nonn

AUTHOR

Sara Billey and Matjaz Konvalinka, Jul 9 2024

STATUS

editing