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

Author

Marko Riedel, Feb 08 2022

Keywords

• nonn

Links

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

Crossrefs

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

Formula

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