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 A124488 #9 Mar 27 2020 09:02:59
%S A124488 3,45,6450,18000,22785,41790,54180,77385,87675,98385,103005,104520,
%T A124488 151515,187005,210210,244590,256620,320775,329175,354795,382875,
%U A124488 387975,431385,495540,509355,528510,632775,763815,804870,810540,812175,849285
%N A124488 Numbers k such that 2*k-1, 4*k-1, 6*k-1, 8*k-1 and 10*k-1 are primes.
%H A124488 Amiram Eldar, <a href="/A124488/b124488.txt">Table of n, a(n) for n = 1..10000</a>
%t A124488 Select[Range[900000], And @@ PrimeQ /@ ({2, 4, 6, 8, 10}*# - 1) &] (* _Ray Chandler_, Nov 21 2006 *)
%Y A124488 Cf. A124485-A124492.
%K A124488 nonn
%O A124488 1,1
%A A124488 _Artur Jasinski_, Nov 04 2006