A268842 Number of sequences with n copies each of 1,2,...,6 and longest increasing subsequence of length 6.

1, 248749, 20117051281, 1077273394836829, 47342758641593552281, 1878320344216429026862153, 70803267480031877368227941803, 2612508237897293571677286548812861, 96042041352156959435669839199503441435, 3553102771891168237056005934820411063204249

Offset: 1

Author

Alois P. Heinz, Feb 14 2016

Keywords

• nonn

Links

• Alois P. Heinz, Table of n, a(n) for n = 1..100 (terms n=1..50 from Vaclav Kotesovec)
• J. D. Horton and A. Kurn, Counting sequences with complete increasing subsequences, Congressus Numerantium, 33 (1981), 75-80. MR 681905

Crossrefs

Column k=6 of A047909.

Formula

a(n) ~ 6^(6*n + 1/2) / (2*Pi*n)^(5/2). - Vaclav Kotesovec, Feb 21 2016