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

Author

Philippe Deléham, Apr 25 2004

Keywords

• easy
• nonn

Formula

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