OFFSET
1,1
COMMENTS
Suggested by N. J. A. Sloane and Robert G. Wilson v.
a(5) > 10^12.
a(5) > 10^13. - Giovanni Resta, Mar 29 2013
a(5) > 10^18. - Hiroaki Yamanouchi, Aug 23 2018
Any term x of this sequence can be combined with any term y of A101223 to satisfy the property (sigma(x)+sigma(y))/(x+y) = 2, which is a necessary (but not sufficient) condition for two numbers to be amicable. - Timothy L. Tiffin, Sep 13 2016
EXAMPLE
n = 34358296576. sigma(n)-2*n = 10.
MATHEMATICA
Select[Range[1, 10^8], DivisorSigma[1, #] - 2 # == 10 &] (* Vincenzo Librandi, Sep 15 2016 *)
PROG
(PARI) for(n=1, 10^8, if(sigma(n)-2*n==10, print1(n ", ")))
(Magma) [n: n in [1..9*10^6] | (SumOfDivisors(n)-2*n) eq 10]; // Vincenzo Librandi, Sep 15 2016
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Donovan Johnson, Mar 23 2013
STATUS
approved