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 A027015 #7 Oct 21 2019 16:49:37 %S A027015 1,12,343,3864,26990,140455,599801,2228414,7486615,23370193,69141497, %T A027015 196766283,544680787,1478898009,3962865228,10526310127,27802386717, %U A027015 73170829088,192150938490,503938185601,1320621962194,3459303317894,9059231670566,23721098636714 %N A027015 a(n) = A027011(2n, n+4). %K A027015 nonn %O A027015 4,2 %A A027015 _Clark Kimberling_ %E A027015 More terms from _Sean A. Irvine_, Oct 21 2019