A045653 Number of 2n-bead balanced binary strings, rotationally equivalent to reverse.

1, 2, 6, 8, 38, 52, 216, 268, 1062, 1232, 4956, 5524, 21848, 24000, 95780, 102808, 410662, 437548, 1748592, 1847524, 7384988, 7759144, 31033404, 32449828, 129774936, 135207552, 540807104, 561629852, 2246432996, 2326762744, 9306937416, 9617286180, 38468731942

Offset

0,2

Links

Andrew Howroyd, Table of n, a(n) for n = 0..1000

Formula

Inverse Moebius transform of A045662. - Andrew Howroyd, Sep 15 2019

Prog

(PARI) c(n)={sumdiv(n, d, moebius(d)*d)} \\ A023900
a(n)={if(n<1, n==0, 2*sumdiv(n, d, c(n/d) * d * binomial(d-d%2, d\2)))} \\ Andrew Howroyd, Sep 15 2019

Crossrefs

Cf. A000984, A023900, A045662, A045654, A045655, A045656.

Sequence in context: A094678 A076507 A117542 * A235320 A152158 A291782

Adjacent sequences: A045650 A045651 A045652 * A045654 A045655 A045656

Keyword

nonn

Author

David W. Wilson

Extensions

Terms a(30) and beyond from Andrew Howroyd, Sep 15 2019

Status

approved