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 A294296 #30 Oct 31 2017 06:31:52 %S A294296 1,1,1,1,1,5,1,1,7,25,1,1,11,43,193,1,1,19,91,409,1481,1,1,35,223, %T A294296 1105,3841,16021,1,1,67,595,3505,13841,50431,167665,1,1,131,1663, %U A294296 12193,60841,230731,648187,2220065,1,1,259,4771,44689,297761,1340851,3955771 %N A294296 Square array A(n,k), n >= 0, k >= 0, read by antidiagonals, where column k is the expansion of e.g.f.: exp(Sum_{j>=1} sigma_k(j) * x^j). %H A294296 Seiichi Manyama, <a href="/A294296/b294296.txt">Antidiagonals n = 0..139, flattened</a> %F A294296 A(0,k) = 1 and A(n,k) = (n-1)! * Sum_{j=1..n} j*sigma_k(j)*A(n-j,k)/(n-j)! for n > 0. %e A294296 Square array A(n,k) begins: %e A294296 1, 1, 1, 1, 1, ... %e A294296 1, 1, 1, 1, 1, ... %e A294296 5, 7, 11, 19, 35, ... %e A294296 25, 43, 91, 223, 595, ... %e A294296 193, 409, 1105, 3505, 12193, ... %e A294296 1481, 3841, 13841, 60841, 297761, ... %Y A294296 Columns k=0..2 give A294363, A294361, A294362. %Y A294296 Rows n=0-1 give A000012. %Y A294296 Main diagonal gives A294388. %Y A294296 Cf. A144048. %K A294296 nonn,tabl %O A294296 0,6 %A A294296 _Seiichi Manyama_, Oct 30 2017