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 A294254 #17 Oct 27 2017 13:11:12 %S A294254 1,1,0,1,-1,0,1,-1,1,0,1,-1,-1,-1,0,1,-1,-1,11,1,0,1,-1,-1,5,-23,-1,0, %T A294254 1,-1,-1,5,25,-101,1,0,1,-1,-1,5,1,-41,991,-1,0,1,-1,-1,5,1,199,-1769, %U A294254 -1849,1,0,1,-1,-1,5,1,79,-1409,7181,-24751,-1,0,1,-1,-1,5 %N A294254 Square array A(n,k), n >= 0, k >= 0, read by antidiagonals, where column k is the expansion of e.g.f.: exp(Product_{j=1..n} (1-x^j) - 1). %H A294254 Seiichi Manyama, <a href="/A294254/b294254.txt">Antidiagonals n = 0..139, flattened</a> %F A294254 B(j,k) is the coefficient of Product_{i=1..k} (1-x^i). %F A294254 A(0,k) = 1 and A(n,k) = (n-1)! * Sum_{j=1..min(A000217(k),n)} j*B(j,k)*A(n-j,k)/(n-j)! for n > 0. %e A294254 Square array A(n,k) begins: %e A294254 1, 1, 1, 1, 1, ... %e A294254 0, -1, -1, -1, -1, ... %e A294254 0, 1, -1, -1, -1, ... %e A294254 0, -1, 11, 5, 5, ... %e A294254 0, 1, -23, 25, 1, ... %e A294254 0, -1, -101, -41, 199, ... %Y A294254 Columns k=0..5 give A000007, A033999, A294255, A294256, A294257, A294258. %Y A294254 Rows n=0 gives A000012. %Y A294254 Main diagonal gives A294260. %Y A294254 Cf. A294250. %K A294254 sign,tabl %O A294254 0,19 %A A294254 _Seiichi Manyama_, Oct 26 2017