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 A293530 #20 Oct 13 2017 05:23:05 %S A293530 1,1,0,1,-1,0,1,-1,1,0,1,-1,-1,-7,0,1,-1,-1,5,25,0,1,-1,-1,-1,-23, %T A293530 -181,0,1,-1,-1,-1,25,-41,1201,0,1,-1,-1,-1,1,-101,1111,-10291,0,1,-1, %U A293530 -1,-1,1,139,-209,-6259,97777,0,1,-1,-1,-1,1,19,-569,251,-16015 %N A293530 Square array A(n,k), n >= 0, k >= 1, read by antidiagonals, where column k is the expansion of e.g.f. 1/Product_{j > 0, j mod k > 0} exp(x^j). %H A293530 Seiichi Manyama, <a href="/A293530/b293530.txt">Antidiagonals n = 0..139, flattened</a> %F A293530 E.g.f. of column k: exp((Sum_{j=1..k-1} x^j)/(x^k - 1)). %e A293530 Square array begins: %e A293530 1, 1, 1, 1, 1, ... %e A293530 0, -1, -1, -1, -1, ... %e A293530 0, 1, -1, -1, -1, ... %e A293530 0, -7, 5, -1, -1, ... %e A293530 0, 25, -23, 25, 1, ... %e A293530 0, -181, -41, -101, 139, ... %Y A293530 Columns k=1..3 give A000007, A293532, A293533. %Y A293530 Rows n=0 gives A000012. %Y A293530 Main diagonal gives A293116. %Y A293530 Cf. A293525. %K A293530 sign,tabl %O A293530 0,14 %A A293530 _Seiichi Manyama_, Oct 11 2017