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 A214631 #33 Sep 14 2018 16:49:38 %S A214631 1,1,1,1,2,1,1,6,16,1,1,20,936,192,1,1,70,85800,379366,2816,1,1,252, %T A214631 9962680,1825221320,249664758,46592,1,1,924,1340103744,14336196893200, %U A214631 89261675900020,221005209058,835584,1 %N A214631 Number A(n,k) of solid standard Young tableaux of shape [[(n)^(k+1)],[n]^k]; square array A(n,k), n>=0, k>=0, read by antidiagonals. %H A214631 Alois P. Heinz, <a href="/A214631/b214631.txt">Antidiagonals n = 0..12</a> %H A214631 S. B. Ekhad, D. Zeilberger, <a href="https://arxiv.org/abs/1202.6229">Computational and Theoretical Challenges on Counting Solid Standard Young Tableaux</a>, arXiv:1202.6229v1 [math.CO], 2012 %H A214631 Wikipedia, <a href="https://en.wikipedia.org/wiki/Young_tableau">Young tableau</a> %e A214631 Square array A(n,k) begins: %e A214631 1, 1, 1, 1, 1, ... %e A214631 1, 2, 6, 20, 70, ... %e A214631 1, 16, 936, 85800, 9962680, ... %e A214631 1, 192, 379366, 1825221320, 14336196893200, ... %e A214631 1, 2816, 249664758, 89261675900020, 70351928759681296000, ... %p A214631 b:= proc(l) option remember; local m; m:= nops(l); %p A214631 `if`({map(x-> x[], l)[]}={0}, 1, add(add(`if`(l[i][j]> %p A214631 `if`(i=m or nops(l[i+1])<j, 0, l[i+1][j]) and l[i][j]> %p A214631 `if`(nops(l[i])=j, 0, l[i][j+1]), b(subsop(i=subsop( %p A214631 j=l[i][j]-1, l[i]), l)), 0), j=1..nops(l[i])), i=1..m)) %p A214631 end: %p A214631 A:= (n, k)-> b([[n$(k+1)], [n]$k]): %p A214631 seq(seq(A(n, d-n), n=0..d), d=0..8); %t A214631 b[l_] := b[l] = With[{m = Length[l]}, If[Union[Flatten[l]] == {0}, 1, Sum[Sum[If[l[[i, j]] > If[i == m || Length[l[[i+1]] ] < j, 0, l[[i+1, j]] ] && l[[i, j]] > If[Length[l[[i]] ] == j, 0, l[[i, j+1]] ], b[ReplacePart[l, i -> ReplacePart[l[[i]], j -> l[[i, j]]-1]]], 0], {j, 1, Length[l[[i]] ]}], {i, 1, m}]]]; a[n_, k_] := b[{Array[n&, k+1], Sequence @@ Array[{n}&, k]}]; Table[Table[a[n, d-n], {n, 0, d}], {d, 0, 8}] // Flatten (* _Jean-François Alcover_, Dec 18 2013, translated from Maple *) %Y A214631 Columns k=0-2 give: A000012, A006335, A214638. %Y A214631 Rows n=0-1 give: A000012, A000984. %Y A214631 Cf. A213932, A213978, A214637, A214722. %K A214631 nonn,tabl %O A214631 0,5 %A A214631 _Alois P. Heinz_, Jul 26 2012