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A119827 Number of ternary words with exactly one 000. 2
0, 0, 0, 1, 4, 16, 60, 212, 728, 2444, 8064, 26256, 84576, 270048, 855936, 2696080, 8446912, 26341696, 81812544, 253181888, 781005440, 2402311616, 7370247168, 22558917120, 68901651456, 210037106688, 639127277568, 1941624275200 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,5

COMMENTS

Except for the initial three zeros, convolution of A077835 with itself. Column 1 of A119825.

LINKS

Table of n, a(n) for n=0..27.

Index entries for linear recurrences with constant coefficients, signature (4,0,-4,-12,-8,-4).

FORMULA

G.f.=z^3/(1-2z-2z^2-2z^3)^2.

EXAMPLE

a(4)=4 because we have 0001, 0002, 1000 and 2000.

MAPLE

h:=z^3/(1-2*z-2*z^2-2*z^3)^2: hser:=series(h, z=0, 33): seq(coeff(hser, z, n), n=0..30);

CROSSREFS

Cf. A077835, A119825, A119826.

Sequence in context: A121254 A261519 A262591 * A089883 A089932 A120926

Adjacent sequences:  A119824 A119825 A119826 * A119828 A119829 A119830

KEYWORD

nonn,easy

AUTHOR

Emeric Deutsch, May 26 2006

STATUS

approved

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Last modified August 22 20:23 EDT 2019. Contains 326182 sequences. (Running on oeis4.)