login
A185378
Number of binary necklaces of 2n beads that are identical when turned over yet cannot be cut to produce a palindrome.
0
1, 3, 6, 15, 28, 62, 120, 255, 496, 1020, 2016, 4094, 8128, 16376
OFFSET
1,2
COMMENTS
These necklaces have bilateral symmetry across axes that involve only vertices. a(n) = A029744(2n) - A185333(2n). Conjecture: a(n) = 2^n - 2^((n - 2^t)/(2^(t+1))), where t = number of factors of 2 in n.
CROSSREFS
Sequence in context: A069712 A076971 A103529 * A285563 A285543 A318396
KEYWORD
nonn
AUTHOR
Tony Bartoletti, Feb 20 2011
STATUS
approved