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 A239389 #10 Jan 14 2017 15:08:36
%S A239389 1,2,3,4,7,8,11,13,32,35,40,47,50,100,118,130,178,208,220,250,254,320,
%T A239389 353,380,401,404,466,487,598,640,652,676,680,692
%N A239389 The record values of d for the n in A239388.
%t A239389 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][[2]]
%Y A239389 Cf. A069003 (least number d such that n^2 + d^2 is prime).
%K A239389 nonn,more
%O A239389 1,2
%A A239389 _T. D. Noe_, Mar 18 2014
%E A239389 a(24)-a(31) from _Giovanni Resta_, Mar 18 2014
%E A239389 a(32)-a(34) from _Emmanuel Vantieghem_, Jan 13 2017