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 A023147 #18 Jul 24 2021 08:36:15
%S A023147 1,2,3,9,16,33,40073,40078,40082,40083,40122,251721,251722,251734,
%T A023147 251736,4124584,10553433,10553439,10553444,10553454,10553478,10553552,
%U A023147 10553553,10553818,27067098,27067524,179992912,465769814,465769832,465769839
%N A023147 Numbers k such that prime(k) == 5 (mod k).
%H A023147 Giovanni Resta, <a href="/A023147/b023147.txt">Table of n, a(n) for n = 1..68</a>
%t A023147 p = 1; Do[ If[ Mod[p = NextPrime[p], n] == 5, Print[n]], {n, 1, 10^9}] (* _Robert G. Wilson v_, Feb 18 2004 *)
%Y A023147 Cf. A171432, A092047, A023143, A023144, A023145, A023146, A023148, A023149, A023150, A023151, A023152.
%K A023147 nonn
%O A023147 1,2
%A A023147 _David W. Wilson_
%E A023147 More terms from _Robert G. Wilson v_, Feb 18 2004
%E A023147 a(24)-a(27) from _Robert G. Wilson v_, Feb 18 2004
%E A023147 Three missing initial terms at start of sequence inserted by _Zak Seidov_, Feb 05 2009