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A081605
Numbers having at least one 0 in their ternary representation.
10
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
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
KEYWORD
nonn,base
AUTHOR
Reinhard Zumkeller, Mar 23 2003
STATUS
approved