A297183 - OEIS

A297183

Number of open binary words of length n.

0, 0, 2, 4, 10, 20, 44, 92, 194, 396, 820, 1684, 3432, 6972, 14144, 28636, 57890, 116828, 235500, 474304, 954444, 1919364, 3857548, 7748888, 15558988, 31229384, 62662088, 125696800, 252079196, 505423476, 1013189208, 2030729700, 4069562810, 8154257184, 16336840080, 32726819744, 65553540096

(list; graph; refs; listen; history; text; internal format)

OFFSET

0,3

COMMENTS

Equals 2^n - A226452(n).

LINKS

Table of n, a(n) for n=0..36.

Gabriele Fici, Open and Closed Words, in Giovanni Pighizzini, ed., The Formal Language Theory Column, Bulletin of EATCS, 2017.

CROSSREFS

Cf. A226452.

Sequence in context: A323445 A307768 A370583 * A232466 A003407 A151523

Adjacent sequences: A297180 A297181 A297182 * A297184 A297185 A297186

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, Dec 28 2017

STATUS

approved