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 A378187 #4 Jan 14 2025 09:50:08
%S A378187 4,12,12,12,24,12,24,12,12,36,12,24,48,24,60,12,48,72,12,36,192,12,60,
%T A378187 24,12,48,12,12,108,48,60,24,72,72,168,36,24,12,84,48,24,48,108,24,24,
%U A378187 36,12,12,12,24,60,48,60,156,48,60,84,12,24,60,84,12,84,36
%N A378187 With p(n) = A002145(n) = n-th non-Pythagorean prime, a(n) is the least k such p(n) + k is a non-Pythagorean prime and 2 p(n) + k - 3 is a Pythagorean prime; and a(n) = 0 if there is no such k.
%e A378187 3 + 4 = 7, the least non-Pythagorean prime after 3,
%e A378187 and 3 + 7 - 3 = 7, a Pythagorean prime, so a(1) = 4.
%t A378187 s = Select[Prime[Range[450]], Mod[#, 4] == 3 &]
%t A378187 a[n_] := Select[Range[200], MemberQ[s, s[[n]] + #] && PrimeQ[2 s[[n]] + # - 3] &, 1]
%t A378187 Flatten[Table[a[n], {n, 1, 140}]]
%Y A378187 Cf. A000041, A002144, A002145, A378186.
%K A378187 nonn
%O A378187 1,1
%A A378187 _Clark Kimberling_, Jan 13 2025