|
%I #8 Nov 11 2019 16:02:55
%S 0,-1,-1,1,-1,24,-1,49,14,82,-1,1700,-1,172,201,993,-1,5793,-1,7958,
%T 409,448,-1,331716,94,634,689,21896,-1,809928,-1,32705,1041,1102,1177,
%U 10077605,-1,1384,1465,2559910,-1,3111600,-1,85100,91047,2044,-1,254803844,286,124907
%N Difference between product of divisors of n and sum of divisors of n.
%C a(p)=-1 iff p is a prime.
%H Metin Sariyar, <a href="/A076721/b076721.txt">Table of n, a(n) for n = 1..5000</a>
%t Table[d = Divisors[n]; Apply[Times, d] - Apply[Plus, d], {n, 1, 50}]
%Y Equals A007955 - A000203.
%K sign
%O 1,6
%A Emrehan Halici (emrehan(AT)halici.com.tr), Oct 27 2002
%E Edited by _Robert G. Wilson v_, Oct 29 2002
|
