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 A245714 #11 Jul 30 2014 12:34:48 %S A245714 1,1,2,1,2,1,3,0,2,1,2,1,3,0,2,1,2,1,4,0,2,1,3,0,3,0,2,1,2,1,3,0,0,0, %T A245714 2,1,3,0,2,1,2,1,4,0,2,1,3,0,4,0,2,1,3,0,3,0,2,1,2,1,3,0,0,0,2,1,3,0, %U A245714 2,1,2,1,3,0,0,0,2,1,4,0,2,1,3,0,4,0,2,1,4,0,3,0,0,0,2,1,3,0,2,1,2,1,3,0,2,1,2,1,5,0,2,1,4,0,4,0,0,0,5 %N A245714 Least number k > 0 such that n + k! is prime, or 0 if no such k exists. %C A245714 a(n) <= n for all n. Thus a(n) = 0 is definite. %H A245714 Vaclav Kotesovec, <a href="/A245714/b245714.txt">Table of n, a(n) for n = 1..5000</a> %e A245714 7 + 1! = 8 is not prime. %e A245714 7 + 2! = 9 is not prime. %e A245714 7 + 3! = 13 is prime. Thus a(7) = 3. %o A245714 (PARI) %o A245714 a(n)=for(k=1,n,if(ispseudoprime(n+k!),return(k))) %o A245714 vector(150,n,a(n)) %Y A245714 Cf. A245723. %K A245714 nonn %O A245714 1,3 %A A245714 _Derek Orr_, Jul 30 2014