This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A268840 #18 Mar 11 2016 11:59:02 %S A268840 1,641,195709,46922017,10258694241,2176464012941,460827731023773, %T A268840 98540942707986273,21364658238692907265,4697818999010952011441, %U A268840 1046430770756355786405517,235755137688345453796236397,53640184515807269993604743389,12308974812428409561104536925709 %N A268840 Number of sequences with n copies each of 1,2,3,4 and longest increasing subsequence of length 4. %H A268840 Alois P. Heinz, <a href="/A268840/b268840.txt">Table of n, a(n) for n = 1..400</a> %H A268840 J. D. Horton and A. Kurn, Counting sequences with complete increasing subsequences, Congressus Numerantium, 33 (1981), 75-80. <a href="http://www.ams.org/mathscinet-getitem?mr=681905">MR 681905</a> %H A268840 Vaclav Kotesovec, <a href="/A268840/a268840.txt">Recurrence (of order 4)</a> %F A268840 a(n) ~ 2^(8*n-1/2) / (Pi*n)^(3/2). - _Vaclav Kotesovec_, Feb 21 2016 %Y A268840 Column k=4 of A047909. %K A268840 nonn %O A268840 1,2 %A A268840 _Alois P. Heinz_, Feb 14 2016