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A069216
Numbers n such that sigma(n) = reversal(n).
6
1, 69, 276, 639, 2556
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
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
KEYWORD
base,nonn
AUTHOR
Joseph L. Pe, Apr 11 2002
STATUS
approved