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 A218386 #15 Aug 11 2021 04:38:22 %S A218386 2,5,19,257,196687 %N A218386 a(n) = A215929(n) - (-1)^Fibonacci(n+1)*A218086(n). %Y A218386 Cf. A215929, A218086. %K A218386 nonn,less %O A218386 0,1 %A A218386 _Raphie Frank_, Oct 27 2012