|
%I #11 Oct 15 2019 23:54:28
%S 3,13,5,11,7,29,3,7,11,15797,5,53,3,11,17,10949,7,
%T 109912203092239643840221,3,43,23,461,5,11,3,109,5,59,7,
%U 568972471024107865287021434301977158534824481,3,67,5,31,13,149,3,7,11,83,13,173,3,19,47
%N Least prime factor of Sum_{k=0..n-1} n^k.
%C The sequence of largest prime factors of numbers generated by the same sum is probably identical to sequence A006486, since (n^n - 1)/(1 + n^2 + ... + n^(n-1)) = n-1.
%H Chai Wah Wu, <a href="/A125571/b125571.txt">Table of n, a(n) for n = 2..178</a>
%e The sum 1 + 4 + 4^2 + 4^3 = 85 = 5 * 17 so the third term is 5.
%o (PARI) a(n) = factor(sum(k=0, n-1, n^k))[1, 1]; \\ _Michel Marcus_, Aug 20 2013
%Y Cf. A006486.
%Y Least prime factors of A023037.
%K nonn
%O 2,1
%A _Axel Harvey_, Jan 02 2007
%E More terms from _Michel Marcus_, Aug 20 2013
|
