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 A279099 #12 Mar 29 2017 19:43:36
%S A279099 59,177,221,260,285,431,476,489,625,653,686,860,957,1320,1334,1734,
%T A279099 1987,2140,2215,2854,2991,3051,3341,3455,3535,3591,3645,3695,3798,
%U A279099 4020,4032,4079,4612,4614,4856,4904,5019,5234,5263,5842,6178,6184,6491,6639,6745,7151
%N A279099 Numbers k such that prime(k) divides primorial(j) + 1 for exactly two integers j.
%C A279099 As used here, "primorial(j)" refers to the product of the first j primes, i.e., A002110(j).
%C A279099 Primorial(j) + 1 is the j-th Euclid number, A006862(j).
%H A279099 Giovanni Resta, <a href="/A279099/b279099.txt">Table of n, a(n) for n = 1..5000</a>
%e A279099 59 is in this sequence because prime(59) = 277 divides primorial(j) + 1 for exactly two integers j: 7 and 17.
%e A279099 436 is not in this sequence because prime(436) = 3041 divides primorial(j) + 1 for exactly three integers j: 206, 263, and 409.
%t A279099 np[1]=1; np[n_] := Block[{c=0, p=Prime[n], trg, x=1}, trg = p-1; Do[x = Mod[x Prime[k], p]; If[trg == x, c++], {k, n-1}]; c]; Select[Range[1000], np[#] == 2 &] (* _Giovanni Resta_, Mar 29 2017 *)
%Y A279099 Subsequence of A279097 (which includes all numbers k such that prime(k) divides primorial(j) + 1 for one or more integers j); cf. A279098 (exactly one integer j).
%Y A279099 Cf. A000040, A002110, A006862, A113165, A279098, A283928.
%K A279099 nonn
%O A279099 1,1
%A A279099 _Jon E. Schoenfield_, Mar 24 2017