A217211 Number of binary sequences of length n with curling number 2.

0, 2, 2, 6, 12, 26, 52, 110, 214, 438, 876, 1762, 3524, 7084, 14144, 28360, 56720, 113542, 227084, 454448, 908804, 1818168, 3636336, 7273614, 14547228, 29096678, 58192994, 116390424, 232780848, 465569860, 931139720, 1862297158, 3724592874, 7449221168, 14898442336, 29796952652, 59593905304

Offset: 1

Author

N. J. A. Sloane, Oct 01 2012

Keywords

• nonn

Links

• N. J. A. Sloane, Table of n, a(n) for n = 1..104 [Entries up through 51 found by direct search (see triangle A216955), later entries obtained from a recurrence.]

Crossrefs

Column 2 of A216955. Cf. A122536, A217212.

Extensions

a(33)-a(37) from Allan Wilks, Oct 06 2012