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 A024689 #3 Mar 30 2012 18:55:59 %S A024689 4,10,39,55,125,165,302,365,591,682,1006,1144,1602,1782,2374,2620, %T A024689 3386,3685,4650,5005,6162,6607,8003,8519,10176,10768,12676,13382, %U A024689 15596,16388,18888,19815,22660,23689,26907,28038,31601,32889,36865,38272,42626,44210 %N A024689 a(n) = s(1)s(n) + s(2)s(n-1) + ... + s(k)s(n+1-k), where k = [ (n+1)/2 ], s = A001950 (upper Wythoff sequence). %K A024689 nonn %O A024689 1,1 %A A024689 _Clark Kimberling_