A053814 - OEIS

%I #14 Dec 15 2017 13:44:01

%S 0,0,1,0,0,0,1,1,2,0,12,0,4,6,1,0,18,0,20,10,8,0,24,1,10,1,0,0,30,0,1,

%T 3,14,9,36,0,16,5,40,0,42,0,4,12,20,0,48,1,7,9,6,0,54,4,56,11,26,0,60,

%U 0,28,22,1,8,66,0,10,15,70,0,72,0,34,26,12,1,78,0,80

%N a(n) = n modulo (sum of proper divisors of n).

%H Antti Karttunen, <a href="/A053814/b053814.txt">Table of n, a(n) for n = 2..16385</a>

%t Table[Mod[n,DivisorSigma[1,n]-n],{n,2,80}] (* _Harvey P. Dale_, Sep 01 2014 *)

%o (PARI) a(n) = n % (sigma(n) - n) \\ _Michel Marcus_, Jul 27 2013

%Y Cf. A001065.

%K nonn

%O 2,9

%A _Henry Bottomley_, Mar 28 2000