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 A219311 #30 Sep 08 2021 06:50:57 %S A219311 1,0,1,0,1,0,1,2,0,1,3,0,1,9,0,1,14,16,0,1,34,35,0,1,55,134,0,1,125, %T A219311 435,0,1,209,1213,768,0,1,461,3454,2310,0,1,791,10484,11407,0,1,1715, %U A219311 28249,44187,0,1,3002,80302,200044,0,1,6434,231895,680160,292864 %N A219311 Number T(n,k) of standard Young tableaux for partitions of n into exactly k distinct parts; triangle T(n,k), n>=0, 0<=k<=A003056(n), read by rows. %C A219311 T(n,k) is defined for n,k >= 0. The triangle contains only the terms with k<=A003056(n). T(n,k) = 0 for k>A003056(n). %H A219311 Alois P. Heinz, <a href="/A219311/b219311.txt">Rows n = 0..100, flattened</a> %H A219311 Wikipedia, <a href="https://en.wikipedia.org/wiki/Young_tableau">Young tableau</a> %e A219311 A(4,2) = 3: %e A219311 +---------+ +---------+ +---------+ %e A219311 | 1 2 3 | | 1 2 4 | | 1 3 4 | %e A219311 | 4 .-----+ | 3 .-----+ | 2 .-----+ %e A219311 +---+ +---+ +---+ %e A219311 Triangle T(n,k) begins: %e A219311 1; %e A219311 0, 1; %e A219311 0, 1; %e A219311 0, 1, 2; %e A219311 0, 1, 3; %e A219311 0, 1, 9; %e A219311 0, 1, 14, 16; %e A219311 0, 1, 34, 35; %e A219311 0, 1, 55, 134; %e A219311 0, 1, 125, 435; %e A219311 0, 1, 209, 1213, 768; %e A219311 0, 1, 461, 3454, 2310; %e A219311 0, 1, 791, 10484, 11407; %e A219311 ... %p A219311 h:= proc(l) local n; n:=nops(l); add(i, i=l)!/mul(mul(1+l[i]-j+ %p A219311 add(`if`(l[k]>=j, 1, 0), k=i+1..n), j=1..l[i]), i=1..n) %p A219311 end: %p A219311 g:= proc(n, i, k, l) `if`(n=0, h(l), `if`(n>k*(i-(k-1)/2), 0, %p A219311 g(n, i-1, min(k, i-1), l)+`if`(i>n, 0, g(n-i, i-1, k-1, [l[], i])))) %p A219311 end: %p A219311 A:= proc(n, k) option remember; `if`(k<0, 0, g(n, n, k, [])) end: %p A219311 T:= (n, k)-> A(n, k) -A(n, k-1): %p A219311 seq(seq(T(n, k), k=0..floor((sqrt(1+8*n)-1)/2)), n=0..20); %t A219311 h[l_] := With[{n = Length[l]}, Sum[i, {i, 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 A219311 g[n_, i_, k_, l_] := If[n == 0, h[l], If[n > k*(i-(k-1)/2), 0, g[n, i-1, Min[k, i-1], l] + If[i > n, 0, g[n-i, i-1, k-1, Append[l, i]]]]]; %t A219311 a[n_, k_] := a[n, k] = If[k < 0, 0, g[n, n, k, {}]]; %t A219311 t[n_, k_] := a[n, k] - a[n, k-1]; %t A219311 Table[Table[t[n, k], {k, 0, Floor[(Sqrt[1+8*n]-1)/2]}], {n, 0, 20}] // Flatten (* _Jean-François Alcover_, Dec 17 2013, translated from Maple *) %Y A219311 Columns k=0-10 give: A000007, A000012 (for n>0), A047171(n) = A037952(n)-1, A219316, A219317, A219318, A219319, A219320, A219321, A219322, A219323. %Y A219311 Row sums give: A218293. %Y A219311 Row lengths are 1 + A003056(n). %Y A219311 T(A000217(k),k) = A005118(k+1). %Y A219311 Cf. A219272, A219274. %K A219311 nonn,tabf %O A219311 0,8 %A A219311 _Alois P. Heinz_, Nov 17 2012