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 A143842 #2 Mar 31 2012 10:31:22 %S A143842 1,1,0,1,1,0,1,1,1,0,1,1,1,1,0,1,1,1,1,1,0,1,1,1,1,2,1,0,1,1,1,1,2,3, %T A143842 1,0,1,1,1,1,2,3,7,1,0,1,1,1,1,2,3,7,11,1,0,1,1,1,1,2,3,7,11,20,1,0,1, %U A143842 1,1,1,2,3,7,11,20,29,1,0,1,1,1,1,2,3,7,11,20,30,45,1,0,1,1,1,1,2,3,7,11,20 %N A143842 Table read by antidiagonals: T(n,k) is the number of strongly connected directed multigraphs with loops with n arcs and k vertices, which are transitive (the existence of a path between two points implies the existence of an arc between those two points). %C A143842 Partial sums of the rows of A139625, i.e., T(n,k) = sum(T139625(n,p),p=0..k). %C A143842 If k>=floor(sqrt(n)), T(n,k) = A139630(n). %Y A143842 Cf. A138352, A136868, A143841. %K A143842 nonn,tabl %O A143842 0,26 %A A143842 _Benoit Jubin_, Sep 02 2008