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 A174272 #4 Mar 30 2012 18:52:39 %S A174272 1,2,5,7,9,10,14,15,16,18,20,22,24,28,29,30,55,67,84,94,116,122,150, %T A174272 174,213,221,228,233,266,336,390,452,545,689,694,784,850,1110,1704, %U A174272 1736,2008,2139,2191,2321,2367,2370,3237,3954,4002,4060,4062,4552,5547,5630 %N A174272 Exactly one of 2^n-3 and 2^n+3 is prime. %C A174272 Numbers n which are in A050414 or in A057732 but not in both. [From _R. J. Mathar_, Mar 29 2010] %e A174272 a(1)=1 because 2^1-3=-1 is nonprime and 2^1+3=5 is prime. %Y A174272 Cf. A050414, A057732. %K A174272 nonn %O A174272 1,2 %A A174272 _Juri-Stepan Gerasimov_, Mar 14 2010 %E A174272 Corrected by _Charles R Greathouse IV_, Mar 20 2010