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 A171907 #4 Jun 02 2025 02:23:18 %S A171907 24,15,20,0,0,1 %N A171907 a(n)= Number of 5 X 5 permutation matrices with trace n and determinant +1. %e A171907 a(0)=24 because we have 24 different permutation matrices 5 x 5 with trace 0 and determinant +1. %Y A171907 A171806, A171808, A171809, A171906, A171908 %K A171907 fini,full,nonn %O A171907 0,1 %A A171907 _Artur Jasinski_, Dec 31 2009