cp's OEIS Frontend

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.

A241427 Smallest prime of the form n^k - k^n for some k, or 0 if no such prime exists.

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%I A241427 #24 Aug 11 2014 23:38:27
%S A241427 7,2,3,6102977801,5,79792265017612001,7,2486784401
%N A241427 Smallest prime of the form n^k - k^n for some k, or 0 if no such prime exists.
%C A241427 Conjecture: a(n) > 0 for all n not in A097764.
%C A241427 More terms in b-file. If n > 4 and in A097764, n^k - k^n is factorable and won't be prime.
%C A241427 a(17) > 17^7500 - 7500^17. See A239279.
%H A241427 Derek Orr, <a href="/A241427/b241427.txt">Table of n, a(n) for n = 2..16</a>
%o A241427 (PARI)
%o A241427 a(n)=k=1;if(n>4,forprime(p=1,100,if(ispower(n)&&ispower(n)%p==0&&n%p==0,return(0));if(n%p==n,break)));k=1;while(!ispseudoprime(n^k-k^n),k++);return(n^k-k^n)
%o A241427 vector(15, n, a(n+1))
%Y A241427 Cf. A078201.
%K A241427 nonn
%O A241427 2,1
%A A241427 _Derek Orr_, Aug 08 2014