A211966 Number of binary sequences of length 2n and curling number 1.

2, 6, 20, 74, 286, 1124, 4460, 17768, 70930, 283440, 1133200, 4531686, 18124522, 72493652, 289965744, 1159845258, 4639345612, 18557311624, 74229104872, 296916136278, 1187663978718, 4750654782144, 19002616863186, 76010462922018

Offset

1,1

Comments

Equivalently, number of binary sequences of length 2n with no initial repeats (see A122536).

Links

Table of n, a(n) for n=1..24.

B. Chaffin, J. P. Linderman, N. J. A. Sloane and Allan Wilks, On Curling Numbers of Integer Sequences, arXiv:1212.6102

B. Chaffin, J. P. Linderman, N. J. A. Sloane and Allan Wilks, On Curling Numbers of Integer Sequences, Journal of Integer Sequences, Vol. 16 (2013), Article 13.4.3.

Index entries for sequences related to curling numbers

Formula

a(n) = 2*A093371(2n) = A093371(2n+1) = A211965(n+1)/2.

Crossrefs

Bisection of A122536.

Cf. A093371, A211965, A216955, A216958.

Sequence in context: A376811 A150152 A107284 * A150153 A150154 A006850

Adjacent sequences: A211963 A211964 A211965 * A211967 A211968 A211969

Keyword

nonn

Author

Omar E. Pol, Nov 28 2012

Status

approved