A055256 Number of odd digits in 3^n.

1, 1, 1, 1, 1, 1, 2, 2, 2, 3, 3, 5, 4, 5, 3, 4, 3, 5, 3, 4, 3, 5, 7, 6, 4, 3, 5, 7, 6, 6, 7, 9, 7, 10, 9, 11, 11, 10, 12, 11, 10, 11, 14, 12, 10, 11, 12, 12, 11, 14, 14, 17, 9, 13, 14, 16, 18, 12, 10, 15, 15, 13, 11, 15, 12, 19, 15, 18, 19, 19, 20, 20, 18, 19, 21, 20, 21, 22

Offset

0,7

Links

Seiichi Manyama, Table of n, a(n) for n = 0..10000

Mathematica

Table[Count[IntegerDigits[3^n], _?OddQ], {n, 0, 80}] (* Harvey P. Dale, Feb 01 2026 *)

Prog

(PARI) a(n) = #select(x->((x%2) == 1), digits(3^n)); \\ Michel Marcus, Nov 22 2019

Crossrefs

Cf. A055255, A034888.

Sequence in context: A139821 A248972 A077563 * A369985 A295630 A029147

Adjacent sequences: A055253 A055254 A055255 * A055257 A055258 A055259

Keyword

nonn,base,easy

Author

Asher Auel, May 05 2000

Status

approved