|
| |
|
|
A119852
|
|
Number of ternary words with exactly one 012.
|
|
1
| |
|
|
0, 0, 0, 1, 6, 27, 106, 387, 1350, 4566, 15102, 49113, 157622, 500520, 1575558, 4923536, 15290784, 47235771, 145246224, 444814533, 1357368786, 4128880561, 12523521786, 37888119522, 114358226428, 344437708131, 1035409733820
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 0,5
|
|
|
COMMENTS
| Except for the initial three zeros, convolution of A076264 with itself. Column 1 of A119851.
|
|
|
FORMULA
| G.f.=z^3/(1-3z+z^2)^2.
|
|
|
EXAMPLE
| a(4)=6 because we have 0012, 0120, 0121, 0122, 1012 and 2012.
|
|
|
MAPLE
| G:=z^3/(1-3*z+z^3)^2: Gser:=series(G, z=0, 34): seq(coeff(Gser, z, n), n=0..30);
|
|
|
CROSSREFS
| Cf. A076264, A119851.
Sequence in context: A000395 A005325 A099623 * A027471 A037695 A094829
Adjacent sequences: A119849 A119850 A119851 * A119853 A119854 A119855
|
|
|
KEYWORD
| nonn
|
|
|
AUTHOR
| Emeric Deutsch (deutsch(AT)duke.poly.edu), May 26 2006
|
| |
|
|
