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 A174838 #3 Mar 30 2012 18:52:39 %S A174838 1,2,4,8,16,21,27,35,55,58,76,84,111,113,120,143,147,155,176,183,218, %T A174838 252,258,265,294,304,348,377,383,387,403,424,435,444,464,525,548,582, %U A174838 585,593,600,633,690,694,732,787,803,810,827,841,846,877,892,900,971 %N A174838 Numbers n such that semiprime(n)+1 is prime, where semiprime(n) is A001358. %C A174838 N is in the sequence iff semiprime(n) is of the form 2p where p is a Sophie Germain prime (A005384). %e A174838 a(1)=1 because semiprime(1)+1=5=prime, a(2)=2 because semiprime(2)+1=7=prime, a(3)=4 because semiprime(4)+1=11=prime. %Y A174838 Cf. A000040, A001358, A005384. %K A174838 nonn %O A174838 1,2 %A A174838 _Juri-Stepan Gerasimov_, Mar 30 2010 %E A174838 Edited, corrected and extended by _Ray Chandler_, Apr 05 2010