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 A138393 #4 May 03 2018 10:29:44
%S A138393 17,33,41,57,65,73,89,97,105,113,129,137,145,153,161,177,185,193,201,
%T A138393 209,217,233,241,249,257,265,273,281,297,305,313,321,329,337,345,353,
%U A138393 369,377,385,393,401,409,417,425,433,449,457,465,473,481,489,497,505
%N A138393 Numbers of form 8k+1 which are not squares.
%t A138393 a = {}; Do[If[Sqrt[8k + 1] == Floor[Sqrt[8k + 1]],[null],AppendTo[a, 8k + 1]], {k, 0, 100}]; a
%t A138393 Select[8*Range[80]+1,!IntegerQ[Sqrt[#]]&] (* _Harvey P. Dale_, May 03 2018 *)
%Y A138393 Cf. A004768, A017077.
%K A138393 nonn
%O A138393 1,1
%A A138393 _Artur Jasinski_, Mar 18 2008