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 A219275 #19 Nov 02 2022 14:45:12 %S A219275 1,1,3,25,1069,368168,1299366501,55208013380403,32401197537296758130, %T A219275 297072961835477978342245712,47538199827835784548062928051198402, %U A219275 146779873623344672821145371965795071455181183,9581411392319396646028223743176779937161862866453789852 %N A219275 Number of standard Young tableaux for partitions of nonnegative integers into distinct parts with largest part n. %H A219275 Alois P. Heinz, <a href="/A219275/b219275.txt">Table of n, a(n) for n = 0..22</a> %H A219275 Wikipedia, <a href="https://en.wikipedia.org/wiki/Young_tableau">Young tableau</a> %e A219275 a(2) = 3: %e A219275 +------+ +------+ +------+ %e A219275 | 1 2 | | 1 3 | | 1 2 | %e A219275 | 3 .--+ | 2 .--+ +------+ %e A219275 +---+ +---+ %p A219275 h:= proc(l) local n; n:=nops(l); add(i, i=l)!/mul(mul(1+l[i]-j+ %p A219275 add(`if`(l[k]>=j, 1, 0), k=i+1..n), j=1..l[i]), i=1..n) %p A219275 end: %p A219275 b:= (n, l)-> `if`(n<1, h(l), b(n-1, l) +b(n-1, [l[], n])): %p A219275 a:= n-> `if`(n=0, 1, b(n-1, [n])): %p A219275 seq(a(n), n=0..12); %t A219275 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 A219275 b[n_, l_] := If[n < 1, h[l], b[n - 1, l] + b[n - 1, Append[l, n]]]; %t A219275 a[n_] := If[n == 0, 1, b[n - 1, {n}]]; %t A219275 Table[a[n], {n, 0, 12}] (* _Jean-François Alcover_, Nov 02 2022, after _Alois P. Heinz_ *) %Y A219275 Column sums of A219274. %Y A219275 First differences of A219273. %K A219275 nonn %O A219275 0,3 %A A219275 _Alois P. Heinz_, Nov 17 2012