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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 (list; graph; refs; listen; history; internal format)
OFFSET

1,1

FORMULA

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

CROSSREFS

Sequence in context: A034445 A054754 A054755 * A162216 A032158 A103745

Adjacent sequences:  A093328 A093329 A093330 * A093332 A093333 A093334

KEYWORD

easy,nonn

AUTHOR

DELEHAM Philippe (kolotoko(AT)wanadoo.fr), Apr 25 2004

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Last modified February 16 17:11 EST 2012. Contains 205938 sequences.