A350229 a(n) is the sum of n and the balanced ternary digits in n.

0, 2, 2, 4, 6, 4, 6, 8, 8, 10, 12, 12, 14, 16, 12, 14, 16, 16, 18, 20, 20, 22, 24, 22, 24, 26, 26, 28, 30, 30, 32, 34, 32, 34, 36, 36, 38, 40, 40, 42, 44, 38, 40, 42, 42, 44, 46, 46, 48, 50, 48, 50, 52, 52, 54, 56, 56, 58, 60, 58, 60, 62, 62, 64, 66, 66, 68

Offset: 0

Author

Rémy Sigrist, Jan 09 2022

Keywords

• nonn
• base
• easy

Comments

The image of this sequence is the set of nonnegative even numbers (A005843).

Examples

			For n = 42:
- the balanced ternary representation of 42 is "1TTT0",
- so a(42) = 42 + 1 - 1 - 1 - 1 + 0 = 40.
		

Crossrefs

See A062028, A092391, A230641 for similar sequences.

Cf. A005843, A065363, A174658 (fixed points).

Programs

Mathematica

Array[# + Total[If[First@ # == 0, Rest@ #, #] &[Prepend[IntegerDigits[#, 3], 0] //. {x___, y_, k_ /; k > 1, z___} :> {x, y + 1, k - 3, z}]] &, 70, 0] (* Michael De Vlieger, Jan 15 2022 *)

PARI

a(n) = my (v=n, d); while (n, n=(n-d=[0,1,-1][1+n%3])/3; v+=d); v

Formula

a(n) = n + A065363(n).

a(n) = n iff n belongs to A174658.