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 A139461 #8 Aug 06 2017 22:54:54
%S A139461 1,2,3,4,8,9,11,12,27,28,37,47,64,321,415,1222,1649,2937,3600,6149,
%T A139461 12481
%N A139461 Numbers k such that 2*prime(k+2) + product (first k odd primes) is prime, i.e., k such that primorial(k+1)/2 + 2*prime(k+2) is prime.
%C A139461 a(22) > 25000. - _Robert Price_, Aug 06 2017
%t A139461 k = 1; a = {}; Do[k = k*Prime[n]; If[PrimeQ[k + 2*Prime[n + 1]], AppendTo[a, n - 1]], {n, 2, 2000}]; a (* _Artur Jasinski_ *)
%Y A139461 Cf. A067026, A067027, A139439, A139440, A139441, A139442, A139443, A139444, A139445, A139446, A139447, A139448, A139449, A139450, A139451, A139452, A139453, A139454, A139455, A139456, A139457, A103514, A139460, A139462, A139463.
%K A139461 nonn
%O A139461 1,2
%A A139461 _Artur Jasinski_, Apr 22 2008
%E A139461 a(16)-a(21) from _Robert Price_, Aug 06 2017