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 A237759 #35 Mar 09 2014 04:57:20 %S A237759 1,2,4,7,21,25,30,33,41,45,57,63,83,100,131,142,144,147,150,175,198, %T A237759 225,304,425,449,469,513,651,782,858,1345,1839,1883,1913,2177,2551, %U A237759 2907,3638,3675,6071,6076,9297,11037,11743,12135,12876,14641,38685,40857 %N A237759 Numbers n such that either n^2*2^n-1 or n^2*2^n+1 is prime, but not both. %e A237759 4 is in the sequence because 4^2*2^4 - 1 = 16*16 - 1 = 255 is not a prime number but 4^2*2^4 + 1 = 16*16 + 1 = 257 is a prime number. %o A237759 (PARI) isok(n) = isp1 = isprime(2^n*n^2-1); isp2 = isprime(2^n*n^2+1); (isp1 || isp2 && !(isp1 && isp2)); \\ _Michel Marcus_, Mar 05 2014 %Y A237759 Cf, A058781, A058780. %K A237759 nonn,less %O A237759 1,2 %A A237759 _Juri-Stepan Gerasimov_, Feb 24 2014 %E A237759 Corrected by _R. J. Mathar_, Feb 26 2014