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 A373899 #33 Jun 28 2024 21:28:13
%S A373899 6,15,21,33,35,55,65,77,85,91,133,143,145,155,161,187,209,217,221,247,
%T A373899 253,265,299,301,323,341,377,391,403,415,437,451,481,493,533,545,551,
%U A373899 553,559,581,589,611,629,667,671,689,697,703,713,781,793,799,817,893,899,901
%N A373899 Semiprimes q*p such that q^p == p (mod (q - p)), where q > p.
%e A373899 15 = 3*5 is a term because 5^3 == 3 (mod 2).
%t A373899 seqQ[n_] := Module[{f = FactorInteger[n], p, q}, If[f[[;; , 2]] == {1, 1}, p = f[[1, 1]]; q = f[[2, 1]]; PowerMod[q, p, q - p] == Mod[p, q - p], False]]; Select[Range[1000], seqQ] (* _Amiram Eldar_, Jun 26 2024 *)
%Y A373899 Subsequence of A001358.
%Y A373899 Cf. A037074 (subsequence), A046388, A371811.
%K A373899 nonn
%O A373899 1,1
%A A373899 _Juri-Stepan Gerasimov_, Jun 22 2024