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A168649 a(n) = (1/n)*Sum_{d|n} moebius(d)*2^(n^2/d). 0
2, 6, 168, 16320, 6710880, 11453201760, 80421421917312, 2305843008676823040, 268650182136584246132736, 126765060022822827559679531520, 241677817415439249618874010960062464 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..11.

FORMULA

a(n) = (1/n)*Sum_{d|n} moebius(n/d)*(2^n)^d.

PROG

(PARI) a(n)=(1/n)*sumdiv(n, d, moebius(d)*2^(n^2/d))

CROSSREFS

Cf. A001037.

Sequence in context: A281819 A329980 A199482 * A135937 A182523 A137532

Adjacent sequences:  A168646 A168647 A168648 * A168650 A168651 A168652

KEYWORD

nonn

AUTHOR

Paul D. Hanna, Dec 01 2009

STATUS

approved

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Last modified August 5 16:48 EDT 2021. Contains 346486 sequences. (Running on oeis4.)