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 A155568 #3 Jul 14 2012 11:32:23
%S A155568 0,1,4,8,9,16,25,29,32,36,37,49,53,64,72,81,100,109,113,116,121,128,
%T A155568 137,144,148,149,169,193,196,197,200,212,225,232,233,256,261,277,281,
%U A155568 288,289,296,317,324,333,337,361,373,389,392,400,401,421,424,436,441,449
%N A155568 Intersection of A001481 inter A020670: N = a^2 + b^2 = c^2 + 7d^2 for some integers a,b,c,d.
%C A155568 Contains A155578 as a subsequence (obtained by restricting a,b,c,d to be nonzero). Also contains A000290 (squares) as subsequence.
%o A155568 (PARI) isA155568(n,/* use optional 2nd arg to get other analogous sequences */c=[7,1]) = { for(i=1,#c, for(b=0,sqrtint(n\c[i]), issquare(n-c[i]*b^2) & next(2)); return);1}
%o A155568 for( n=0,500, isA155568(n) & print1(n","))
%Y A155568 Cf. A001481, A002479, A003136, A002481, A020668 ff.
%K A155568 easy,nonn
%O A155568 1,3
%A A155568 _M. F. Hasler_, Jan 25 2009