OFFSET
1,1
PROG
(PARI) isok(m) = sigma(4*m+3) == 6*m; \\ Michel Marcus, Feb 17 2021
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Benoit Cloitre, Feb 04 2002
EXTENSIONS
a(9)-a(17) from Donovan Johnson, Feb 01 2009
STATUS
approved