A093331 - OEIS

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A093331

Number of ternary necklaces of length n with no subsequence 00.

0

2, 5, 8, 17, 32, 76, 164, 398, 948, 2336, 5756, 14460, 36344, 92282, 235120, 602348, 1548320, 3995602, 10340300, 26838896, 69830576, 182111414, 475898036, 1246011050, 3267979208, 8584907756, 22585675348, 59501499506, 156955442072

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OFFSET

1,1

LINKS

Table of n, a(n) for n=1..29.

FORMULA

a(n) = (1/n)*sum_{d divides n } totient(n/d)*A080040(d).

CROSSREFS

Sequence in context: A316795 A054754 A054755 * A162216 A032158 A103745

Adjacent sequences: A093328 A093329 A093330 * A093332 A093333 A093334

KEYWORD

easy,nonn

AUTHOR

Philippe Deléham, Apr 25 2004

STATUS

approved