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 A152808 #2 Mar 30 2012 18:37:15 %S A152808 1,1,4,10,29,93,310,1106,4205,16912,71858,321921,1516429,7493126, %T A152808 38758968,209453249,1180293354,6923457745,42206892713,267002169884, %U A152808 1750266527588,11873506488390,83253781992093,602667751464027 %N A152808 Column 3 of triangle A152798; a(n) = A152798(n+3,3). %F A152808 a(n) = A152798(n+2,3) + 3*A152798(n+2,4) + 3*A152798(n+2,5) + A152798(n+2,6). %Y A152808 Cf. A152798; A122889, A152799, A152809. %K A152808 nonn %O A152808 0,3 %A A152808 _Paul D. Hanna_, Jan 01 2009