A118732 Numbers n such that 3^n has odd digit sum.

0, 1, 2, 3, 4, 5, 9, 10, 11, 13, 14, 16, 17, 18, 20, 21, 22, 25, 26, 27, 30, 31, 32, 34, 35, 36, 39, 41, 45, 48, 51, 52, 53, 59, 60, 61, 62, 63, 65, 66, 68, 69, 73, 74, 76, 78, 79, 80, 81, 86, 87, 89, 91, 92, 98, 99, 100, 101, 103, 105, 108, 113, 114, 115, 117, 118, 119, 121

Offset

1,3

Comments

Numbers n such that A000244(n) is in A054684. - Robert Israel, Jun 28 2017

Links

Robert Israel, Table of n, a(n) for n = 1..10000

Maple

select(t -> convert(convert(3^t, base, 10), `+`)::odd, [$0..1000]); # Robert Israel, Jun 28 2017

Mathematica

Select[Range[0, 121], Mod[ Plus @@ IntegerDigits[3^# ], 2] == 1 &] (* Ray Chandler, Jun 10 2006 *)
Select[Range[0, 200], OddQ[Total[IntegerDigits[3^#]]]&] (* Harvey P. Dale, Dec 30 2021 *)

Prog

(PARI) isok(n) = (sumdigits(3^n) % 2) == 1; \\ Michel Marcus, Jun 28 2017

Crossrefs

Cf. A000244, A054684, A118731, A118735.

Sequence in context: A095906 A333050 A328119 * A118872 A046029 A303600

Adjacent sequences: A118729 A118730 A118731 * A118733 A118734 A118735

Keyword

base,nonn

Author

Zak Seidov, May 22 2006

Status

approved