

A158422


a[n] = number of bit strings of length n which have exactly as many substrings 000 as substrings 111.


1



1, 2, 4, 6, 10, 16, 28, 46, 82, 142, 256, 460, 846, 1556, 2912, 5454, 10332, 19618, 37506, 71894, 138432, 267136, 517142, 1002904, 1949366, 3794686, 7399060, 14444992, 28236426, 55251992, 108224818, 212167258, 416284478, 817369732
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OFFSET

0,2


REFERENCES

This was motivated by problem 11424 in the 2009 March issue of the American Mathematical monthly.


LINKS

R. H. Hardin, Table of n, a(n) for n=0..500
Shalosh B. Ekhad and Doron Zeilberger, Automatic Solution of Richard Stanley's Amer. Math. Monthly Problem #11610 and ANY Problem of That Type, arXiv preprint arXiv:1112.6207, 2011. See subpages for rigorous derivations of g.f., recurrence, asymptotics for this sequence.


CROSSREFS

Sequence in context: A052185 A136241 A160444 * A018161 A288599 A067880
Adjacent sequences: A158419 A158420 A158421 * A158423 A158424 A158425


KEYWORD

nonn


AUTHOR

Dan Jurca (dan.jurca(AT)csueastbay.edu), Mar 18 2009


EXTENSIONS

a(11)a(500)from R. H. Hardin, Aug 10 2009


STATUS

approved



