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 A176191 #7 Nov 21 2013 12:50:02
%S A176191 1,2,5,14,22,25,52,62,88,100,126,133,142,169,188,198,202,222,229,263,
%T A176191 299,321,340,354,359,364,388,407,426,465,478,504,539,556,577,579,611,
%U A176191 668,700,722,737,781,797,814,857,905,916,932,984,1033,1108,1118,1148
%N A176191 Numbers n such that semiprime(n)-1 is prime, where semiprime(n) is A001358.
%e A176191 a(1)=1 because semiprime(1)-1=3=prime, a(2)=2 because semiprime(2)-1=5=prime, a(3)=5 because semiprime(5)-1=13=prime.
%t A176191 nn=5000;With[{sps=Select[Range[nn],PrimeOmega[#]==2&]},Transpose[ Select[ Thread[ {sps,Range[ Length[sps]]}],PrimeQ[First[#]-1]&]][[2]]] (* _Harvey P. Dale_, Jul 19 2011 *)
%Y A176191 Cf. A174838.
%K A176191 nonn
%O A176191 1,2
%A A176191 _Juri-Stepan Gerasimov_, Apr 11 2010
%E A176191 Corrected (478 inserted) by _R. J. Mathar_, Apr 13 2010