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A218126 Number of 9-ary sequences with primitive period n. 2
1, 9, 72, 720, 6480, 59040, 530640, 4782960, 43040160, 387419760, 3486725280, 31381059600, 282428998560, 2541865828320, 22876787671920, 205891132034880, 1853020145805120, 16677181699666560, 150094634909047920, 1350851717672992080, 12157665455570137920 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Seiichi Manyama, Table of n, a(n) for n = 0..1047 (terms 0..350 from Alois P. Heinz)

FORMULA

a(n) = Sum_{d|n} 9^d * mu(n/d) for n>0, a(0) = 1.

MAPLE

with(numtheory):

a:= n-> `if`(n=0, 1, add(9^d*mobius(n/d), d=divisors(n))):

seq(a(n), n=0..30);

CROSSREFS

Column k=9 of A143324.

Sequence in context: A001809 A006135 A180836 * A133672 A043079 A099973

Adjacent sequences:  A218123 A218124 A218125 * A218127 A218128 A218129

KEYWORD

nonn

AUTHOR

Alois P. Heinz, Oct 21 2012

STATUS

approved

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Last modified November 16 12:40 EST 2018. Contains 317272 sequences. (Running on oeis4.)