A137599 - OEIS

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A137599

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

1

7142167, 75018277, 71859221859

(list; graph; refs; listen; history; text; internal format)

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

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