A268840 Number of sequences with n copies each of 1,2,3,4 and longest increasing subsequence of length 4.

1, 641, 195709, 46922017, 10258694241, 2176464012941, 460827731023773, 98540942707986273, 21364658238692907265, 4697818999010952011441, 1046430770756355786405517, 235755137688345453796236397, 53640184515807269993604743389, 12308974812428409561104536925709

Offset: 1

Author

Alois P. Heinz, Feb 14 2016

Keywords

• nonn

Links

• Alois P. Heinz, Table of n, a(n) for n = 1..400
• J. D. Horton and A. Kurn, Counting sequences with complete increasing subsequences, Congressus Numerantium, 33 (1981), 75-80. MR 681905
• Vaclav Kotesovec, Recurrence (of order 4)

Crossrefs

Column k=4 of A047909.

Formula

a(n) ~ 2^(8*n-1/2) / (Pi*n)^(3/2). - Vaclav Kotesovec, Feb 21 2016