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 A215553 #16 Aug 29 2025 04:14:55 %S A215553 1,8,135,2574,51765,1072764,22664655,485325150,10495906641, %T A215553 228723580800,5014392953273,110471247622008,2443644577217025, %U A215553 54238301397083592,1207358254510786125,26943600312354592800,602594302548520646793,13502992968597378745800 %N A215553 a(n) = binomial(9*n,n)*(7*n+1)/(8*n+1). %C A215553 Number of standard Young tableaux of shape [8n,n]. %H A215553 Alois P. Heinz, <a href="/A215553/b215553.txt">Table of n, a(n) for n = 0..225</a> %H A215553 Wikipedia, <a href="https://en.wikipedia.org/wiki/Young_tableau">Young tableau</a>. %F A215553 a(n) = C(9*n,n)*(7*n+1)/(8*n+1). %F A215553 a(n) = [x^n] ((1 - sqrt(1 - 4*x))/(2*x))^(7*n+1). - _Ilya Gutkovskiy_, Nov 01 2017 %F A215553 a(n) ~ 7 * 3^(18*n+1) / (2^(24*n+5) * sqrt(Pi*n)). - _Amiram Eldar_, Aug 29 2025 %p A215553 a:= n-> binomial(9*n,n)*(7*n+1)/(8*n+1): %p A215553 seq(a(n), n=0..20); %t A215553 a[n_] := Binomial[9*n,n]*(7*n+1)/(8*n+1); Array[a, 21, 0] (* _Amiram Eldar_, Aug 29 2025 *) %Y A215553 Column k=8 of A214776. %K A215553 nonn,changed %O A215553 0,2 %A A215553 _Alois P. Heinz_, Aug 15 2012