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 A219272 #36 Feb 09 2017 09:17:27 %S A219272 1,1,1,1,1,1,2,1,1,1,3,3,5,16,1,1,1,3,4,9,25,49,70,168,768,1,1,1,3,4, %T A219272 10,30,63,162,372,1506,3300,7887,15015,48048,292864,1,1,1,3,4,10,31, %U A219272 69,182,525,1911,5115,17347,43758,149721,626769,1946516,4934930 %N A219272 Number A(n,k) of standard Young tableaux for partitions of n into distinct parts with largest part <= k; triangle A(n,k), k>=0, 0<=n<=k*(k+1)/2, read by columns. %C A219272 A(n,k) is defined for n,k >= 0. A(n,k) = 0 iff n > k*(k+1)/2 = A000217(k). The triangle contains only the nonzero terms. A(n,k) = A(n,n) for k>=n. %H A219272 Alois P. Heinz, <a href="/A219272/b219272.txt">Columns k = 0..22, flattened</a> %H A219272 Wikipedia, <a href="https://en.wikipedia.org/wiki/Young_tableau">Young tableau</a> %F A219272 T(n,k) = Sum_{i=0..k} A219274(n,i). %e A219272 A(3,2) = 2: %e A219272 +------+ +------+ %e A219272 | 1 2 | | 1 3 | %e A219272 | 3 .--+ | 2 .--+ %e A219272 +---+ +---+ %e A219272 A(3,3) = 3: %e A219272 +------+ +------+ +---------+ %e A219272 | 1 2 | | 1 3 | | 1 2 3 | %e A219272 | 3 .--+ | 2 .--+ +---------+ %e A219272 +---+ +---+ %e A219272 Triangle A(n,k) begins: %e A219272 1, 1, 1, 1, 1, 1, 1, 1, 1, ... %e A219272 . 1, 1, 1, 1, 1, 1, 1, 1, ... %e A219272 . 1, 1, 1, 1, 1, 1, 1, ... %e A219272 . 2, 3, 3, 3, 3, 3, 3, ... %e A219272 . 3, 4, 4, 4, 4, 4, ... %e A219272 . 5, 9, 10, 10, 10, 10, ... %e A219272 . 16, 25, 30, 31, 31, 31, ... %e A219272 . 49, 63, 69, 70, 70, ... %e A219272 . 70, 162, 182, 189, 190, ... %p A219272 h:= proc(l) local n; n:=nops(l); add(i, i=l)!/mul(mul(1+l[i]-j+ %p A219272 add(`if`(l[k]>=j, 1, 0), k=i+1..n), j=1..l[i]), i=1..n) %p A219272 end: %p A219272 g:= proc(n, i, l) local s; s:=i*(i+1)/2; %p A219272 `if`(n=s, h([l[], seq(i-j, j=0..i-1)]), `if`(n>s, 0, %p A219272 g(n, i-1, l)+ `if`(i>n, 0, g(n-i, i-1, [l[], i])))) %p A219272 end: %p A219272 A:= (n, k)-> g(n, k, []): %p A219272 seq(seq(A(n, k), n=0..k*(k+1)/2), k=0..7); %t A219272 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 A219272 g[n_, i_, l_] := g[n, i, l] = With[{s=i*(i+1)/2}, If[n==s, h[Join[l, Table[ i-j, {j, 0, i-1}]]], If[n>s, 0, g[n, i-1, l] + If[i>n, 0, g[n-i, i-1, Append[l, i]]]]]]; %t A219272 A[n_, k_] := g[n, k, {}]; %t A219272 Table[Table[A[n, k], {n, 0, k*(k+1)/2}], {k, 0, 7}] // Flatten (* _Jean-François Alcover_, Feb 29 2016, after _Alois P. Heinz_ *) %Y A219272 Column heights are A000124. %Y A219272 Column sums give: A219273. %Y A219272 Diagonal gives: A218293. %Y A219272 Leftmost nonzero elements give A219339. %Y A219272 Column of leftmost nonzero element is A002024(n) for n>0. %Y A219272 T(A000217(n),n) = A005118(n+1). %K A219272 nonn,tabf %O A219272 0,7 %A A219272 _Alois P. Heinz_, Nov 17 2012