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 A215554 #19 Aug 29 2025 04:15:22
%S A215554 1,9,170,3625,81510,1888460,44602348,1067658735,25810820750,
%T A215554 628737007195,15408077648040,379444514503119,9382177773301060,
%U A215554 232775087755980000,5792018711632340160,144481310070897555910,3611955405113118024990,90470699668284950782170
%N A215554 a(n) = binomial(10*n,n)*(8*n+1)/(9*n+1).
%C A215554 Number of standard Young tableaux of shape [9n,n].
%H A215554 Alois P. Heinz, <a href="/A215554/b215554.txt">Table of n, a(n) for n = 0..215</a>
%H A215554 Wikipedia, <a href="https://en.wikipedia.org/wiki/Young_tableau">Young tableau</a>
%F A215554 a(n) = C(10*n,n)*(8*n+1)/(9*n+1).
%F A215554 a(n) = [x^n] ((1 - sqrt(1 - 4*x))/(2*x))^(8*n+1). - _Ilya Gutkovskiy_, Nov 01 2017
%F A215554 a(n) ~ 2^(10*n+3) * 5^(10*n+1/2) / (3^(18*n+3) * sqrt(Pi*n)). - _Amiram Eldar_, Aug 29 2025
%p A215554 a:= n-> binomial(10*n,n)*(8*n+1)/(9*n+1):
%p A215554 seq(a(n), n=0..20);
%t A215554 Table[Binomial[10n,n] (8n+1)/(9n+1),{n,0,20}] (* _Harvey P. Dale_, Dec 19 2016 *)
%Y A215554 Column k=9 of A214776.
%K A215554 nonn,changed
%O A215554 0,2
%A A215554 _Alois P. Heinz_, Aug 15 2012