OFFSET
1,2
COMMENTS
a(19) > 3000000. - Giovanni Resta, Feb 17 2014
a(23) > 4 * 10^9. - Hiroaki Yamanouchi, Sep 27 2015
EXAMPLE
48 is coprime to 1, 5, 7, 11, 13, 17, 19, 23, 25, 29, 31, 35, 37, 41, 43, 47. When 48 is divided by these numbers the remainders are 0, 3, 6, 4, 9, 14, 10, 2, 23, 19, 17, 13, 11, 7, 5, 1. Their sum is 144 and 144 / 48 = 3.
MAPLE
with(numtheory); P:=proc(q) local i, n, t; for n from 1 to q do t:=0;
for i from 2 to n-1 do if gcd(i, n)=1 then t:=t+(n mod i); fi; od;
if type(t/n, integer) then print(n); fi; od; end: P(10^6);
PROG
(PARI) is(n)=sum(i=1, n-1, if(gcd(n, i)==1, n%i))%n==0 \\ Charles R Greathouse IV, Nov 06 2014
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Paolo P. Lava, Feb 14 2014
EXTENSIONS
a(14) from Michel Marcus, Feb 17 2014
a(15)-a(18) from Giovanni Resta, Feb 17 2014
a(19)-a(22) from Hiroaki Yamanouchi, Sep 27 2015
STATUS
approved