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 A125018 #19 Jul 29 2023 14:35:32
%S A125018 1,5,9,13,17,29,37,41,45,49,53,61,73,81,89,97,101,109,113,117,121,137,
%T A125018 149,153,157,173,181,193,197,229,233,241,245,257,261,269,277,281,293,
%U A125018 313,317,333,337,349,353,361,369,373,389,397,401,405,409,421,433
%N A125018 Numbers == 1 (mod 4) with a unique partition as a sum of 2 squares x^2 + y^2.
%H A125018 Amiram Eldar, <a href="/A125018/b125018.txt">Table of n, a(n) for n = 1..10000</a>
%e A125018 5 = 1^2 + 2^2, 9 = 0^2 + 3^2, 13 = 2^2 + 3^2, 17 = 1^2 + 4^2, 29 = 2^2 + 5^2, ... - _Michael Somos_, Jul 25 2023
%t A125018 Select[4 * Range[0, 100] + 1, Length @ PowersRepresentations[#, 2, 2] == 1 &] (* _Amiram Eldar_, Mar 12 2020 *)
%o A125018 (PARI) isok(n)= {if (n % 4 != 1, return(0)); A000161(n) == 1;} \\ _Michel Marcus_, Nov 02 2013
%Y A125018 Cf. A002145, A119345, A124982, A124983.
%K A125018 nonn
%O A125018 1,2
%A A125018 _Artur Jasinski_, Nov 16 2006
%E A125018 More terms from _Michel Marcus_, Nov 02 2013