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 A330134 #19 Dec 16 2019 08:58:46
%S A330134 1,33,7555,13482049,186481694371,19733690332538577
%N A330134 Number of n X n (-1,0,1)-matrices with zero permanent.
%H A330134 Code Golf Stack Exchange, <a href="https://codegolf.stackexchange.com/q/196712/53884">Find the number of n-by-n (-1, 0, 1) matrices with zero permanent as quickly as possible</a>
%t A330134 a[n_] := Sum[Boole[Permanent[m] == 0], {m, Tuples[{-1, 0, 1}, {n, n}]}];
%Y A330134 Cf. A088672, A057981.
%K A330134 nonn,more,hard
%O A330134 1,2
%A A330134 _Hongyang Cao_, Dec 02 2019
%E A330134 a(6) from _Peter J. Taylor_, Dec 16 2019