OFFSET
1,1
COMMENTS
a(4) > 10^12. - Giovanni Resta, Oct 28 2012
EXAMPLE
sigma(75018277)=77281056=77281057-1=reversal(75018277)-1, so 75018277 is in the sequence.
MATHEMATICA
Do[If[DivisorSigma[1, n]==FromDigits@Reverse@IntegerDigits@n-1, Print[n]], {n, 1553000000}]
CROSSREFS
KEYWORD
base,more,nonn,bref
AUTHOR
Farideh Firoozbakht, Feb 23 2008
EXTENSIONS
a(3) from Giovanni Resta, Oct 28 2012
STATUS
approved