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 A097350 #5 Oct 02 2013 15:12:41 %S A097350 2,3,6,49 %N A097350 Numbers n such that (Sum (2k)^k, k=1..n) - 1 is prime. %C A097350 Some of the larger entries may only correspond to probable primes. %C A097350 Term 49 corresponds to a certified prime (Primo 2.2.0 beta). Next term is greater than 5400. - _Ryan Propper_, Aug 23 2005 %e A097350 6 is a term as 2^1 + 4^2 + 6^3 + 8^4 + 10^5 + 12^6 - 1 = 3090313, which is prime. %o A097350 (PARI) s=-1; for(k=1,830, s=s+(2*k)^k; if(isprime(s), print1(k,","))) %Y A097350 Cf. A073825 (Sum k^k, k=1..n, is prime), A097349 ((Sum (2k)^k, k=1..n) + 1 is prime). %K A097350 nonn %O A097350 1,1 %A A097350 _Rick L. Shepherd_, Aug 07 2004