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 A089476 #5 Feb 16 2015 10:23:22 %S A089476 1,2,4,10,32,136 %N A089476 Number of different values taken by the permanent of a real singular (0,1)-matrix of order n. %e A089476 a(4)=10 because the permanents of singular (0, 1)-matrices can take the values 0, 2, 4, 6, 8, 10, 12, 14, 18, 24. %Y A089476 A089475 gives different permanents of nonsingular (0, 1)-matrices, A089481 occurrence counts for permanents of singular (0, 1)-matrices, A087983 different permanents of all (0, 1)-matrices. %K A089476 hard,nonn %O A089476 1,2 %A A089476 _Hugo Pfoertner_, Nov 11 2003 %E A089476 a(6) from _Jaap Spies_, Nov 28 2003