A023699 -id:A023699 - cp's OEIS frontend

A043329 Duplicate of A023699.

2, 5, 6, 7, 11, 14, 15, 16, 18, 19, 21, 22, 29, 32, 33, 34, 38, 41, 42, 43, 45

Offset: 1

dead

A117592 a(n) = a(3n) = a(3n+1) = a(3n+2)/2 with a(0)=1.

1, 1, 2, 1, 1, 2, 2, 2, 4, 1, 1, 2, 1, 1, 2, 2, 2, 4, 2, 2, 4, 2, 2, 4, 4, 4, 8, 1, 1, 2, 1, 1, 2, 2, 2, 4, 1, 1, 2, 1, 1, 2, 2, 2, 4, 2, 2, 4, 2, 2, 4, 4, 4, 8, 2, 2, 4, 2, 2, 4, 4, 4, 8, 2, 2, 4, 2, 2, 4, 4, 4

Offset: 0

Paul Barry, Apr 05 2006

Row sums of number triangle A117944.
Product of the nonzero digits of (n written in base 3). - Ilya Gutkovskiy, Nov 15 2020
a(n) = 1, 2, 4, 8, 16, 32, 64 iff n is respectively in A005836, A023699, A023700, A023701, A023702, A023703, A023704. - Bernard Schott, Dec 04 2020

Felix Fröhlich, Table of n, a(n) for n = 0..10000 (first 2001 terms from Vincenzo Librandi)

See A338882 for similar sequences.
Cf. A081603 (log_2), A117942 (signed), A117944.
Cf. A005836, A023699, A023700, A023701, A023702, A023703, A023704.

Nest[ Join[#, #, 2#] &, {1}, 5] (* Robert G. Wilson v, Jul 27 2014 *)

a(n) = 1 << hammingweight(digits(n,3)>>1); \\ Kevin Ryde, Nov 15 2020

from gmpy2 import digits
def A117592(n): return 1<Chai Wah Wu, Dec 05 2024

a(n) = a(3n)/a(0) = a(3n+1)/a(1) = a(3n+2)/a(2).
a(n) = abs(A117942(n)).
G.f. A(x) satisfies: A(x) = (1 + x + 2*x^2) * A(x^3). - Ilya Gutkovskiy, Nov 15 2020
a(n) = 2^A081603(n). - Kevin Ryde, Nov 15 2020

a(0) = 1 added to the Name by Bernard Schott, Dec 04 2020

A291907 Numbers such that the nonzero digits in the base 3 expansion consists of two 1s and one 2.

Original entry on oeis.org

14, 16, 22, 32, 34, 38, 42, 46, 48, 58, 64, 66, 86, 88, 92, 96, 100, 102, 110, 114, 126, 136, 138, 144, 166, 172, 174, 190, 192, 198, 248, 250, 254, 258, 262, 264, 272, 276, 288, 298, 300, 306, 326, 330, 342, 378, 406, 408, 414, 432, 490, 496, 498, 514, 516, 522

Offset: 1

Richard Ehrenborg, Sep 05 2017

If k belongs to this sequence, A060350(k) and A291903(k) are divisible by 3.

Amiram Eldar, Table of n, a(n) for n = 1..10000
Richard Ehrenborg and Alex Happ, On the powers of the descent set statistic, arXiv:1709.00778 [math.CO], 2017.

Cf. A007089, A023693, A023699, A060350, A291903.

Select[Range[1000], DigitCount[#, 3, {1, 2}] == {2, 1} &] (* Amiram Eldar, Apr 07 2022 *)

A023693 INTERSECT A023699. - R. J. Mathar, Nov 10 2017

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A043329 Duplicate of A023699.

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A117592 a(n) = a(3n) = a(3n+1) = a(3n+2)/2 with a(0)=1.

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A291907 Numbers such that the nonzero digits in the base 3 expansion consists of two 1s and one 2.

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