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 A089475 #12 May 14 2025 06:48:51 %S A089475 1,1,3,9,31,149 %N A089475 Number of different values taken by the permanent of a real nonsingular (0,1)-matrix of order n. %C A089475 This sequence was first provided by _Jaap Spies_. %e A089475 a(4) = 9 because the permanents of non-singular 4 X 4 (0,1)-matrices can take the values 1,2,..,7,9,11. %Y A089475 Cf. A055165, A089480, A089476. %K A089475 more,nonn %O A089475 1,3 %A A089475 _Hugo Pfoertner_, Nov 11 2003 %E A089475 a(6) from _Jaap Spies_, Nov 12 2003