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 A048456 #6 Oct 14 2019 23:42:17 %S A048456 2,3,7,13,30,56,127,237,530,994,2192,4144,9016,17192,36949,71023, %T A048456 151024,292340,616032,1199556,2508660,4909028,10201810,20044004, %U A048456 41437560,81683022,168134730,332321130,681582636,1350091410,2760703019 %N A048456 First terms from generation 1 onwards. %Y A048456 For "Generations" see A048448-A048455. See also A047844. %K A048456 nonn %O A048456 0,1 %A A048456 _Patrick De Geest_, May 15 1999