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 A239388 #12 Jan 14 2017 07:48:30
%S A239388 1,3,8,9,12,23,30,48,63,114,141,408,651,1173,2697,12639,30963,53343,
%T A239388 159537,283209,289131,335511,601398,1832421,2594214,3533079,4013361,
%U A239388 15717618,17449677,57532827,186891843,226385511,231177657,242117967
%N A239388 Values of n such that n^2 + d^2 is prime for a record first value of d.
%C A239388 See A239389 for the corresponding values of d.
%t A239388 leastK[n_] := Module[{k = 1}, While[! PrimeQ[n^2 + k^2], k++]; k]; nn = 10000; t = {}; kMax = 0; Do[k = leastK[n]; If[k > kMax, kMax = k; AppendTo[t, {n, k}]], {n, nn}]; Transpose[t][[1]]
%Y A239388 Cf. A069003 (least number d such that n^2 + d^2 is prime).
%K A239388 nonn,more
%O A239388 1,2
%A A239388 _T. D. Noe_, Mar 18 2014
%E A239388 a(24)-a(31) from _Giovanni Resta_, Mar 18 2014
%E A239388 a(32)-a(34) from _Emmanuel Vantieghem_, Jan 13 2017