A351364 - OEIS

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A351364

Number of necklaces with n black and n white beads that avoid the pattern BBBB.

1

1, 2, 4, 9, 21, 59, 162, 483, 1453, 4492, 14048, 44616, 142936, 462380, 1506534, 4941955, 16303783, 54066560, 180111432, 602481589, 2022797529, 6814336663, 23026359634, 78027238290, 265085903996, 902733374480, 3080967048004, 10536594982790, 36102498293396, 123920278459564

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OFFSET

1,2

LINKS

Table of n, a(n) for n=1..30.

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

FORMULA

a(n) = A003239(n) - A351363(n).

CROSSREFS

Cf. A351359, A351357, A351358, A351359, A351360, A351361.

Sequence in context: A123458 A048194 A148075 * A058718 A148076 A217976

Adjacent sequences: A351361 A351362 A351363 * A351365 A351366 A351367

KEYWORD

nonn

AUTHOR

Marko Riedel, Feb 08 2022

STATUS

approved