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 A139451 #7 May 21 2017 21:29:17
%S A139451 1,3,6,7,8,13,22,33,53,58,62,142,189,220,479,496,503,760,1464,6503,
%T A139451 9477,13861,23881
%N A139451 Numbers n such that primorial(n)/2 + 256 is prime.
%C A139451 a(24) > 25000. - _Robert Price_, May 21 2017
%t A139451 k = 1/2; a = {}; Do[k = k*Prime[n]; If[PrimeQ[k + 256], Print[n]; AppendTo[a, n]], {n, 325}]; a
%Y A139451 Cf. A067026, A067027, A139439-A139457, A103514.
%K A139451 nonn
%O A139451 1,2
%A A139451 _Artur Jasinski_, Apr 21 2008
%E A139451 a(1)=1 inserted and program corrected, a(15)-a(19) from _Ray Chandler_, Jun 16 2013
%E A139451 a(20)-a(23) from _Robert Price_, May 21 2017