OFFSET
1,1
PROG
(PARI) isok(k) = {my(sk = sigma(k)); for (m=1, k, if ((sk == sigma(m)) && (sk == m + k - gcd(m, k)), return (1)); ); return (0); } \\ Michel Marcus, Oct 27 2019
CROSSREFS
KEYWORD
nonn
AUTHOR
Yasutoshi Kohmoto, Dec 01 2006
EXTENSIONS
Edited by Stefan Steinerberger, Aug 14 2007
More terms from Jinyuan Wang, Feb 07 2022
STATUS
approved