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 A294289 #15 Oct 27 2017 13:10:51 %S A294289 1,1,0,1,-1,0,1,-1,3,0,1,-1,1,-13,0,1,-1,1,-1,73,0,1,-1,1,-7,25,-501, %T A294289 0,1,-1,1,-7,73,-241,4051,0,1,-1,1,-7,49,-421,1081,-37633,0,1,-1,1,-7, %U A294289 49,-181,2641,-3361,394353,0,1,-1,1,-7,49,-301,1561,-32131,68881 %N A294289 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/(1+x^j) - 1). %H A294289 Seiichi Manyama, <a href="/A294289/b294289.txt">Antidiagonals n = 0..139, flattened</a> %F A294289 B(j,k) is the coefficient of Product_{i=1..k} 1/(1+x^i). %F A294289 A(0,k) = 1 and A(n,k) = (n-1)! * Sum_{j=1..n} j*B(j,k)*A(n-j,k)/(n-j)! for n > 0. %e A294289 Square array A(n,k) begins: %e A294289 1, 1, 1, 1, 1, ... %e A294289 0, -1, -1, -1, -1, ... %e A294289 0, 3, 1, 1, 1, ... %e A294289 0, -13, -1, -7, -7, ... %e A294289 0, 73, 25, 73, 49, ... %e A294289 0, -501, -241, -421, -181, ... %Y A294289 Columns k=0..5 give A000007, A293125, A294290, A294291, A294292, A294293. %Y A294289 Rows n=0 gives A000012. %Y A294289 Main diagonal gives A294261. %Y A294289 Cf. A294212. %K A294289 sign,tabl %O A294289 0,9 %A A294289 _Seiichi Manyama_, Oct 27 2017