A091442 Table (by antidiagonals) of permutations of two types of objects such that each cycle contains at least one object of each type. Each type of object is unlabeled.

1, 1, 1, 1, 3, 1, 1, 3, 3, 1, 1, 5, 8, 5, 1, 1, 5, 11, 11, 5, 1, 1, 7, 17, 26, 17, 7, 1, 1, 7, 24, 40, 40, 24, 7, 1, 1, 9, 31, 66, 85, 66, 31, 9, 1, 1, 9, 39, 95, 146, 146, 95, 39, 9, 1, 1, 11, 50, 139, 245, 304, 245, 139, 50, 11, 1, 1, 11, 59, 183, 379, 538, 538, 379, 183, 59, 11

Offset

1,5

References

F. Bergeron, G. Labelle and P. Leroux, Combinatorial Species and Tree-Like Structures, Cambridge, 1998, p. 114 (2.4.42).

Links

Table of n, a(n) for n=1..77.

Formula

G.f.: A(x, y) = Product_{k>=1} (1 - x^n)*(1 - y^n)/(1 - x^n - y^n).

Example

1,  1,  1,  1,  1, ...
1,  3,  3,  5,  5, ...
1,  3,  8, 11, 17, ...
1,  5, 11, 26, 40, ...
1,  5, 17, 40, 85, ...

Crossrefs

Sequence in context: A174546 A134444 A176149 * A392413 A379473 A025834

Adjacent sequences: A091439 A091440 A091441 * A091443 A091444 A091445

Keyword

nonn,tabl

Author

Christian G. Bower, Jan 09 2004

Status

approved