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 A229991 #10 Feb 15 2014 17:57:22
%S A229991 2,3,4,5,6,7,8,9,10,11,13,14,17,19,20,22,26,28,29,33,34,35,41,43,45,
%T A229991 49,52,55,56,57,60,61,64,69,72,75,81,83,85,86,89,90,91,93,94,98,104,
%U A229991 105,109,113,116,120,122,123,124,129,134,138,139,140,142,143
%N A229991 Numbers for which A061214(n) - 1 is prime, where A061214(n) = product of composite numbers between prime(n) and prime(n+1) .
%H A229991 Harvey P. Dale, <a href="/A229991/b229991.txt">Table of n, a(n) for n = 2..1000</a>
%e A229991 a(2) = 2 because 4 - 1 is prime; a(4) = 4 because 8*9*10-1 is prime; 12 is not in A229991 because 38*39*40 - 1 is not prime.
%t A229991 q[n_] := Product[k, {k, Prime[n] + 1, Prime[n + 1] - 1}]; c[n_] := If[PrimeQ[q[n] - 1], 1, 0]; t = Table[c[n], {n, 1, 230}]; u = Flatten[Position[t, 1]]
%t A229991 Select[Range[150],PrimeQ[Times@@Range[Prime[#]+1,Prime[#+1]-1]-1]&] (* _Harvey P. Dale_, Feb 15 2014 *)
%Y A229991 Cf. A061214, A229992.
%K A229991 nonn
%O A229991 2,1
%A A229991 _Clark Kimberling_, Oct 09 2013