0,3

Indexing starts from zero, because a(0) = 0 is a special case.

These numbers correspond to the maximal (lexicographically largest) representatives selected from each equivalence class of those binary necklaces that stay the same (in the same equivalence class) when flipped over (which thus have a bilateral symmetry, please see the examples). A029744(n) gives the number of terms with n significant bits in their binary representation.

Antti Karttunen, Table of n, a(n) for n = 0..5117

28 ("11100" in binary) is in sequence, because after removing the most significant bit, the binary string "1100" when reversed, "0011", can then be rotated (two steps in either direction) to give "1100" again and "1100" is the lexicographically largest of these rotations.

114 ("1110010" in binary) is NOT in the sequence, because after removing the most significant bit, the binary string "110010" when reversed, "010011", does not yield "110010" no matter how many steps it is rotated (even though it is the lexicographically largest rotation of its class). Thus although 114 is in A257250 (a supersequence of this sequence), it is not included here.

(define (isA258209? n) (= n (A256999 (A059893 n))))

(define A258209 (MATCHING-POS 0 0 isA258209?))

Cf. A029744, A059893, A256999.

Subsequence of A257250.

Differs from A257250 for the first time at n=31, where a(31) = 118, while A257250(31) = 114.

Sequence in context: A114391 A328607 A257250 * A391251 A300630 A077436

Adjacent sequences: A258206 A258207 A258208 * A258210 A258211 A258212

nonn,base

Antti Karttunen, May 31 2015

approved