

A118885


Number of binary sequences of length n containing exactly one subsequence 0011.


2



0, 0, 0, 0, 1, 4, 12, 32, 78, 180, 400, 864, 1827, 3800, 7800, 15840, 31884, 63704, 126480, 249760, 490885, 960828, 1873828, 3642560, 7060314, 13649196, 26324704, 50662464, 97309767, 186571248, 357119472, 682524224, 1302589016, 2482706544
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OFFSET

0,6


COMMENTS

Column 1 of A118884.


LINKS

Table of n, a(n) for n=0..33.


FORMULA

G.f.=z^4/(12z+z^4)^2.


EXAMPLE

a(5)=4 because we have 00110,00111,00011 and 10011.


MAPLE

g:=z^4/(12*z+z^4)^2: gser:=series(g, z=0, 40): seq(coeff(gser, z, n), n=0..36);


CROSSREFS

Cf. A118884.
Sequence in context: A107035 A260145 A260778 * A097392 A090634 A260186
Adjacent sequences: A118882 A118883 A118884 * A118886 A118887 A118888


KEYWORD

nonn


AUTHOR

Emeric Deutsch, May 03 2006


STATUS

approved



