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 A027096 #7 Oct 23 2019 20:12:07 %S A027096 1,3,9,31,105,355,1198,4024,13429,44479,146145,476347,1540615,4946425, %T A027096 15774197,49992571,157545775,493946713,1541481630,4790452228, %U A027096 14831036177,45759663403,140751744489,431730577935,1320914941797 %N A027096 a(n) = A027082(n, 2n-9). %K A027096 nonn %O A027096 5,2 %A A027096 _Clark Kimberling_