A351361 Number of binary necklaces with n beads and at least four consecutive black beads.

0, 0, 0, 1, 2, 3, 5, 9, 17, 33, 63, 124, 241, 475, 930, 1831, 3593, 7077, 13905, 27377, 53847, 106006, 208601, 410723, 808514, 1592123, 3135085, 6174695, 12161761, 23957945, 47198847, 92997768, 183253045, 361145269, 711793554, 1403055509, 2765913617

Offset

1,5

Links

Table of n, a(n) for n=1..37.

Marko R. Riedel et al., Necklaces made of black and white beads, Math StackExchange, Feb 2022.

Formula

a(n) = A000031(n) - A280218(n).

Crossrefs

Cf. A351356, A351357, A351358, A351359, A351360.

Sequence in context: A080889 A049858 A092483 * A324767 A005257 A091697

Adjacent sequences: A351358 A351359 A351360 * A351362 A351363 A351364

Keyword

nonn

Author

Marko Riedel, Feb 08 2022

Status

approved