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 A347597 #4 Sep 16 2021 03:47:38 %S A347597 0,2,-12,230,-6936,316682,-20359332,1754340590,-195242324016, %T A347597 27266796955922,-4669829301365052,962523286888757750, %U A347597 -235056895264868039496,67119429827860669710362 %N A347597 a(n) = Permanent(T(2*n + 1)) where T(n) is the tangent matrix defined in A346831. Bisection of A347598 (odd indices). %Y A347597 Cf. A347598, A346831. %K A347597 sign,more %O A347597 0,2 %A A347597 _Peter Luschny_, Sep 14 2021