A069216 Numbers n such that sigma(n) = reversal(n).

1, 69, 276, 639, 2556

Offset: 1

Author

Joseph L. Pe, Apr 11 2002

Keywords

• base
• nonn

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

Examples

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

Programs

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 *)