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A069216 Numbers n such that sigma(n) = reversal(n). 6
1, 69, 276, 639, 2556 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

There is no further term up to 10^10. - Farideh Firoozbakht, Jan 20 2008

There is no further term up to 10^13. - Giovanni Resta, Jul 13 2015

LINKS

Table of n, a(n) for n=1..5.

EXAMPLE

sigma(2556) = 6552 = reversal(2556), so 2556 belongs to the sequence.

MATHEMATICA

Do[If[DivisorSigma[1, n] == FromDigits[Reverse[IntegerDigits[n]]], Print[n]], {n, 1, 10^5}]

Select[Range[3000], DivisorSigma[1, #]==IntegerReverse[#]&] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Aug 29 2017 *)

CROSSREFS

Sequence in context: A296126 A188546 A158732 * A158736 A262456 A161486

Adjacent sequences:  A069213 A069214 A069215 * A069217 A069218 A069219

KEYWORD

base,nonn

AUTHOR

Joseph L. Pe, Apr 11 2002

STATUS

approved

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Last modified August 7 22:44 EDT 2020. Contains 336279 sequences. (Running on oeis4.)