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 A166057 #2 Mar 31 2012 13:21:20
%S A166057 415,1639,2359,3995,5191,5459,7567,7811,8315,8459,8479,9611,9895,9943,
%T A166057 11159,12271,12731,12851,13835,14447,15155,15251,16091,17891,18143,
%U A166057 18319,21059,21755,23055,23411,23435,23815,24395,24535,26143,27179
%N A166057 Integers of the form 4n+3 for which Sum_{i=1..u} J(i,4n+3) obtains value zero exactly 7 times, when u ranges from 1 to (4n+3). Here J(i,k) is the Jacobi symbol.
%C A166057 Fourth row of A166092.
%Y A166057 a(n) = A004767(A166056(n)).
%K A166057 nonn
%O A166057 1,1
%A A166057 _Antti Karttunen_, Oct 08 2009