A169805 Twice the sum of the digits of n.

0, 2, 4, 6, 8, 10, 12, 14, 16, 18, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 14, 16, 18, 20, 22, 24, 26

Offset

0,2

Comments

The only n such that a(n) = n are 0 and 18.

Links

Table of n, a(n) for n=0..76.

Erich Friedman, What's Special About This Number?

Formula

a(n) = 2*A007953(n).

Mathematica

2*Total[IntegerDigits[#]]&/@Range[0, 80] (* Harvey P. Dale, Apr 17 2022 *)

Crossrefs

Cf. A007953.

Sequence in context: A136614 A245627 A097586 * A340479 A263042 A230099

Adjacent sequences: A169802 A169803 A169804 * A169806 A169807 A169808

Keyword

nonn,base

Author

N. J. A. Sloane, May 24 2010

Status

approved