A070856 Numbers n such that sigma(reverse(n)) = phi(n).

1, 120, 260, 450, 861, 1411, 1541, 1550, 7372, 7957, 8393, 9312, 13811, 14840, 20440, 26060, 38323, 41550, 46990, 49813, 51412, 61050, 77695, 78625, 86691, 94604, 94632, 138631, 143520, 166331, 169360, 176820, 182750, 208150, 236220, 236840, 270650

Offset

1,2

Links

Donovan Johnson, Table of n, a(n) for n = 1..1000

Example

sigma(reverse(120)) = sigma(21) = 32 = phi(120), so 120 is a term of the sequence.

Mathematica

Select[ Range[ 10^6 ], EulerPhi[ # ]==DivisorSigma[ 1, FromDigits[ Reverse[ IntegerDigits[ # ] ] ] ]& ]

Crossrefs

Cf. A000203, A000010, A004086, A070835.

Sequence in context: A146950 A028976 A158130 * A211467 A257712 A250607

Adjacent sequences: A070853 A070854 A070855 * A070857 A070858 A070859

Keyword

base,nonn

Author

Joseph L. Pe, May 16 2002

Extensions

Extended by Ray Chandler, Feb 10 2009

Status

approved