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 A139453 #7 May 22 2017 20:00:49
%S A139453 4,5,6,7,9,12,73,129,142,144,253,455,531,734,1009,1193,1553,2449,3309,
%T A139453 13534,17513,17832,22852
%N A139453 Numbers n such that primorial(n)/2 + 512 is prime.
%C A139453 a(24) > 25000. - _Robert Price_, May 22 2017
%t A139453 k = 1/2; a = {}; Do[k = k*Prime[n]; If[PrimeQ[k + 512], Print[n]; AppendTo[a, n]], {n, 325}]; a
%Y A139453 Cf. A067026, A067027, A139439-A139457, A103514.
%K A139453 nonn
%O A139453 1,1
%A A139453 _Artur Jasinski_, Apr 21 2008
%E A139453 a(12)-a(18) from _Ray Chandler_, Jun 16 2013
%E A139453 a(19)-a(23) from _Robert Price_, May 22 2017