OFFSET
1,1
COMMENTS
a(21) > 10^13. - Giovanni Resta, Jul 11 2013
MATHEMATICA
For[n=1, True, n++, If[DivisorSigma[1, n]+DivisorSigma[1, n+1]==3n, Print[n]]]
CROSSREFS
KEYWORD
more,nonn
AUTHOR
Benoit Cloitre, Feb 07 2002
EXTENSIONS
Edited by Dean Hickerson, Feb 16 2002
a(17) from Donovan Johnson, Jan 31 2009
a(18)-a(20) from Giovanni Resta, Jul 11 2013
STATUS
approved