A344853 a(n) = n minus (sum of digits of n in base 3).

0, 0, 0, 2, 2, 2, 4, 4, 4, 8, 8, 8, 10, 10, 10, 12, 12, 12, 16, 16, 16, 18, 18, 18, 20, 20, 20, 26, 26, 26, 28, 28, 28, 30, 30, 30, 34, 34, 34, 36, 36, 36, 38, 38, 38, 42, 42, 42, 44, 44, 44, 46, 46, 46, 52, 52, 52, 54, 54, 54, 56, 56, 56, 60, 60, 60, 62, 62, 62

Offset: 0

Author

Thomas König, May 30 2021

Keywords

• base
• easy
• nonn

Comments

All terms are even.

In all sequences of the form f(n) = n minus (sum of digits of n in base b), every term appears b times consecutively. Here b = 3, hence terms are entries of A346502 repeated 3 times. - Bernard Schott, Jul 21 2021

Examples

			a(20) = 20 - (2 + 0 + 2) = 16 because 20 is written as 202 in base 3.
		

Links

• Michael De Vlieger, Table of n, a(n) for n = 0..10000

Crossrefs

Cf. A011371 (in base 2), A066568 (in base 10).

Cf. A004128, A053735, A054861, A346502.

Programs

Mathematica

a[n_] := n - Plus @@ IntegerDigits[n, 3]; Array[a, 70, 0] (* Amiram Eldar, May 30 2021 *)

PARI

a(n) = n - sumdigits(n, 3); \\ Michel Marcus, Jul 11 2021

Formula

a(n) = n - A053735(n).

a(n) = 2 * A054861(n).

a(n) = 2 * A004128(floor(n/3)).

a(3*n) = a(3*n+1) = a(3*n+2).