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 A077222 #4 Dec 05 2013 19:55:50 %S A077222 1,8,17,32,49,72,9,16,33,48,73,96,25,24,57,64,105,120,169,56,65,104, %T A077222 121,168,193,248,41,40,81,88,137,152,209,80,89,136,153,208,233,128,97, %U A077222 192,249,112,113,176,185,256,273,352,177,184,257,272,353,376,465,160 %N A077222 a(1) = 1 and then alternately the smallest even and odd numbers not occurring earlier such that the sum of two successive terms is a square. %Y A077222 Cf. A077221. %K A077222 nonn %O A077222 0,2 %A A077222 _Amarnath Murthy_, Nov 03 2002 %E A077222 Corrected and extended by _John W. Layman_, Jan 12 2005