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 A219273 #23 Nov 02 2022 14:45:18 %S A219273 1,2,5,30,1099,369267,1299735768,55209313116171,32401252746609874301, %T A219273 297072994236730724952120013,47538200124908778784793653003318415, %U A219273 146779873670882872946054150750588724458499598,9581411392466176519699106616122834087912451590912289450 %N A219273 Number of standard Young tableaux for all partitions of nonnegative integers into distinct parts with largest part <= n. %H A219273 Alois P. Heinz, <a href="/A219273/b219273.txt">Table of n, a(n) for n = 0..22</a> %H A219273 Wikipedia, <a href="https://en.wikipedia.org/wiki/Young_tableau">Young tableau</a> %e A219273 a(2) = 5: %e A219273 +------+ +------+ +------+ +---+ +-+ %e A219273 | 1 2 | | 1 3 | | 1 2 | | 1 | +-+ %e A219273 | 3 .--+ | 2 .--+ +------+ +---+ %e A219273 +---+ +---+ %p A219273 h:= proc(l) local n; n:=nops(l); add(i, i=l)!/mul(mul(1+l[i]-j+ %p A219273 add(`if`(l[k]>=j, 1, 0), k=i+1..n), j=1..l[i]), i=1..n) %p A219273 end: %p A219273 b:= (n, l)-> `if`(n<1, h(l), b(n-1, l) +b(n-1, [l[], n])): %p A219273 a:= n-> b(n, []): %p A219273 seq(a(n), n=0..12); %t A219273 h[l_] := With[{n = Length[l]}, Total[l]!/Product[ Product[1 + l[[i]] - j + Sum[If[l[[k]] >= j, 1, 0], {k, i + 1, n}], {j, 1, l[[i]]}], {i, 1, n}]]; %t A219273 b[n_, l_] := If[n < 1, h[l], b[n - 1, l] + b[n - 1, Append[l, n]]]; %t A219273 a[n_] := b[n, {}]; %t A219273 Table[a[n], {n, 0, 12}] (* _Jean-François Alcover_, Nov 02 2022, after _Alois P. Heinz_ *) %Y A219273 Column sums of A219272. %Y A219273 Partial sums of A219275. %K A219273 nonn %O A219273 0,2 %A A219273 _Alois P. Heinz_, Nov 17 2012