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 A293051 #15 Sep 30 2017 03:10:15 %S A293051 1,1,-1,1,0,0,1,0,-1,1,1,0,0,-1,1,1,0,0,-1,2,-2,1,0,0,0,-1,9,-9,1,0,0, %T A293051 0,-1,-1,9,-9,1,0,0,0,0,-1,9,-50,50,1,0,0,0,0,-1,-1,34,-267,267,1,0,0, %U A293051 0,0,0,-1,-1,90,-413,413,1,0,0,0,0,0,-1,-1,34,-71 %N A293051 Square array A(n,k), n>=0, k>=0, read by antidiagonals, where column k is the expansion of e.g.f. exp(Sum_{i=0..k} x^i/i! - exp(x)). %H A293051 Seiichi Manyama, <a href="/A293051/b293051.txt">Antidiagonals n = 0..139, flattened</a> %F A293051 E.g.f. of column k: Product_{i>k} exp(-x^i/i!). %F A293051 A(0,k) = 1, A(1,k) = A(2,k) = ... = A(k,k) = 0 and A(n,k) = - Sum_{i=k..n-1} binomial(n-1,i)*A(n-1-i,k) for n > k. %e A293051 Square array begins: %e A293051 1, 1, 1, 1, 1, ... %e A293051 -1, 0, 0, 0, 0, ... %e A293051 0, -1, 0, 0, 0, ... %e A293051 1, -1, -1, 0, 0, ... %e A293051 1, 2, -1, -1, 0, ... %e A293051 -2, 9, -1, -1, -1, ... %Y A293051 Columns k=0..4 give A000587, A293037, A293038, A293039, A293040. %Y A293051 Rows n=0..1 give A000012, (-1)*A000007. %Y A293051 Main diagonal gives A000007. %Y A293051 Cf. A229223, A293024. %K A293051 sign,tabl %O A293051 0,20 %A A293051 _Seiichi Manyama_, Sep 29 2017