A151786 a(n) = 8^(wt(n)-1) where wt(n) is the binary weight of n (A000120).

1, 1, 8, 1, 8, 8, 64, 1, 8, 8, 64, 8, 64, 64, 512, 1, 8, 8, 64, 8, 64, 64, 512, 8, 64, 64, 512, 64, 512, 512, 4096, 1, 8, 8, 64, 8, 64, 64, 512, 8, 64, 64, 512, 64, 512, 512, 4096, 8, 64, 64, 512, 64, 512, 512, 4096, 64, 512, 512, 4096, 512, 4096, 4096, 32768, 1, 8, 8, 64, 8, 64

Offset

1,3

Links

Dumitru Damian, Table of n, a(n) for n = 1..10000

Formula

a(n) = 8^A048881(n-1). - _Jon Maiga_ / _Georg Fischer_, Jun 25 2021

Mathematica

8^(DigitSum[Range[100], 2] - 1) (* _Paolo Xausa_, Feb 18 2026 *)

Prog

(PARI) a(n) = 8^(hammingweight(n) - 1); \\ _Michel Marcus_, Jun 26 2021
(Python)
def A151786(n): return 1<<3*(n.bit_count()-1)
print(list(A151786(n) for n in range(1, 10**2)))  # _Dumitru Damian_, Mar 04 2023

Crossrefs

Cf. A000120, A048881.

Sequence in context: A019760 A081816 A092618 * A094770 A093565 A081777

Adjacent sequences: A151783 A151784 A151785 * A151787 A151788 A151789

Keyword

nonn

Author

_N. J. A. Sloane_, Jun 25 2009

Status

approved