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 A278583 #26 Mar 26 2020 19:40:12
%S A278583 12,36,156,540,876,1200,1380,1620,2016,2556,2856,3060,4356,4440,5076,
%T A278583 5580,5700,6336,6636,6660,6996,7416,8220,9180,9660,9900,10836,11496,
%U A278583 12456,12600,12720,12756,13680,14436,15240,16920,17076,18216,18300,18396,19440,21000,21576,22620,23556,24480
%N A278583 Numbers k such that k+1 is a prime, k+2 is twice a prime, and k+3 is three times a prime.
%C A278583 All terms are divisible by 12. - _Daniel Poveda Parrilla_, Dec 12 2016
%D A278583 R. K. Guy, Posting to Number Theory Mailing List, Nov 30 2016
%H A278583 Antti Karttunen and Charles R Greathouse IV, <a href="/A278583/b278583.txt">Table of n, a(n) for n = 1..10000</a> (first 563 terms from Antti Karttunen)
%t A278583 Select[Range[12,25000,12],AllTrue[{#+1,(#+2)/2,(#+3)/3},PrimeQ]&] (* The program uses the AllTrue function from Mathematica version 10 *) (* _Harvey P. Dale_, Mar 26 2020 *)
%o A278583 (PARI) list(lim)=my(v=List()); forprime(p=2,lim+1, if(p%6==1 && isprime(p\2+1) && isprime(p\3+1), listput(v,p-1))); Vec(v) \\ _Charles R Greathouse IV_, Dec 03 2016
%Y A278583 Equals A036570(n) - 1.
%Y A278583 Positions of terms >= 3 in A278500.
%Y A278583 Cf. A074200.
%K A278583 nonn
%O A278583 1,1
%A A278583 _N. J. A. Sloane_, Nov 30 2016