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A091466 Table (by antidiagonals) of labeled alternating octupi with n black nodes and k white nodes. Each type of object labeled from its own label set. 1
1, 2, 2, 0, 14, 0, 0, 36, 36, 0, 0, 24, 336, 24, 0, 0, 0, 1296, 1296, 0, 0, 0, 0, 2160, 14832, 2160, 0, 0, 0, 0, 1440, 80640, 80640, 1440, 0, 0, 0, 0, 0, 233280, 1082880, 233280, 0, 0, 0, 0, 0, 0, 362880, 7776000, 7776000, 362880, 0, 0, 0, 0, 0, 0, 241920, 33264000 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

1,2

REFERENCES

F. Bergeron, G. Labelle and P. Leroux, Combinatorial Species and Tree-Like Structures, Cambridge, 1998, p. 113 (2.4.41).

LINKS

Table of n, a(n) for n=1..60.

FORMULA

Double e.g.f.: A(x, y) = Sum_{i, j>=0} (x^i*y^j/(i!*j!)) = log((1-x*y)^2/(1-x*y*(3+x+y))).

EXAMPLE

1  2    0     0       0 ...

2  4   36    24       0 ...

0 36  336  1296    2160 ...

0 24 1296 14832   80640 ...

0  0 2160 80640 1082880 ...

CROSSREFS

Cf. A029767, A091467.

Sequence in context: A117270 A244137 A181389 * A134085 A151339 A228273

Adjacent sequences:  A091463 A091464 A091465 * A091467 A091468 A091469

KEYWORD

nonn,tabl

AUTHOR

Christian G. Bower, Jan 12 2004

STATUS

approved

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Last modified March 27 04:42 EDT 2017. Contains 284144 sequences.