A081605 Numbers having at least one 0 in their ternary representation.

0, 3, 6, 9, 10, 11, 12, 15, 18, 19, 20, 21, 24, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 42, 45, 46, 47, 48, 51, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 69, 72, 73, 74, 75, 78, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100

Offset

1,2

Comments

Complement of A032924.

A212193(a(n)) <> 0. [Reinhard Zumkeller, May 04 2012]

Links

Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

Mathematica

Select[Range[0, 100], DigitCount[#, 3, 0]>0&] (* Harvey P. Dale, Aug 10 2021 *)

Prog

(Haskell)
import Data.List (findIndices)
a081605 n = a081605_list !! (n-1)
a081605_list = findIndices (/= 0) a212193_list
-- Reinhard Zumkeller, May 04 2012
(Python)
from itertools import count, islice
def A081605_gen(): # generator of terms
    a = -1
    for n in count(2):
        b = int(bin(n)[3:], 3) + (3**(n.bit_length()-1)-1>>1)
        yield from range(a+1, b)
        a = b
A081605_list = list(islice(A081605_gen(), 30)) # Chai Wah Wu, Oct 13 2023

Crossrefs

Cf. A007089, A077267, A081607, A081606, A074940.

Sequence in context: A239977 A074499 A309584 * A293828 A337088 A110263

Adjacent sequences: A081602 A081603 A081604 * A081606 A081607 A081608

Keyword

nonn,base

Author

Reinhard Zumkeller, Mar 23 2003

Status

approved