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 A123983 #14 Mar 27 2020 09:01:32
%S A123983 12,57,162,249,432,564,984,1734,2007,2427,2664,2784,3627,5307,5472,
%T A123983 5727,6399,7614,11082,11547,11607,11694,14127,14274,14484,14862,15117,
%U A123983 17049,19104,19422,20577,25677,27612,27714,28152,29307,32232,34602,35592
%N A123983 Numbers k for which 8*k+1, 8*k+5, 8*k+7 and 8*k+11 are primes.
%H A123983 Amiram Eldar, <a href="/A123983/b123983.txt">Table of n, a(n) for n = 1..10000</a>
%p A123983 isA123983 := proc(n) RETURN( isprime(8*n+1) and isprime(8*n+5) and isprime(8*n+7) and isprime(8*n+11) ) ; end: for n from 1 to 7000 do if isA123983(n) then printf("%d,",n) ; fi ; od ; # _R. J. Mathar_, Nov 06 2006
%t A123983 Select[Range[37000], And @@ PrimeQ /@ ({1, 5, 7, 11} + 8#) &] (* _Ray Chandler_, Nov 05 2006 *)
%Y A123983 Cf. A005122, A005123, A005124, A005125, A105133.
%K A123983 nonn
%O A123983 1,1
%A A123983 _Artur Jasinski_, Oct 30 2006
%E A123983 Edited and extended by _Ray Chandler_ and _R. J. Mathar_, Nov 05 2006