A093331 Number of ternary necklaces of length n with no subsequence 00.

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

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