A137599 Numbers n such that sigma(n)=reversal(n)-1.

7142167, 75018277, 71859221859

Offset

1,1

Comments

a(4) > 10^12. - Giovanni Resta, Oct 28 2012

Links

Table of n, a(n) for n=1..3.

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

Cf. A137598.

Sequence in context: A263069 A034636 A178214 * A151937 A204308 A288481

Adjacent sequences: A137596 A137597 A137598 * A137600 A137601 A137602

Keyword

base,more,nonn,bref

Author

Farideh Firoozbakht, Feb 23 2008

Extensions

a(3) from Giovanni Resta, Oct 28 2012

Status

approved