A080241 Define two sequences by A_n = mex{A_i,B_i : 0 <= i < n} for n >= 0, B_0=0, B_1=1 and for n >= 2, B_n = 2B_{n-1}+(-1)^{A_n}. Sequence gives B_n.

0, 1, 3, 7, 13, 27, 55, 109, 219, 437, 875, 1751, 3501, 7003, 14005, 28011, 56021, 112043, 224085, 448171, 896341, 1792683, 3585365, 7170731, 14341463, 28682925, 57365851, 114731701, 229463403, 458926805, 917853611, 1835707221

Offset

0,3

Comments

The minimal excluded value of set of nonnegative numbers S is mex S = least nonnegative integer not in S.

The sequence A_n is given in A080240.

Links

Table of n, a(n) for n=0..31.

A. S. Fraenkel, Home Page

A. S. Fraenkel, New games related to old and new sequences, INTEGERS, Electronic J. of Combinatorial Number Theory, Vol. 4, Paper G6, 2004.

Crossrefs

Cf. A080240.

Sequence in context: A140465 A333653 A301594 * A098479 A119445 A146904

Adjacent sequences: A080238 A080239 A080240 * A080242 A080243 A080244

Keyword

nonn

Author

Aviezri S. Fraenkel, Mar 12 2003

Extensions

More terms from John W. Layman, May 04 2004

Status

approved