|
Search: id:A007788
|
|
|
| A007788 |
|
Number of augmented Andre 3-signed permutations: expansion of (1-sin 3x)^(-1/3). |
|
+0
3
|
|
| 1, 1, 4, 19, 136, 1201, 13024, 165619, 2425216, 40132801, 740882944, 15091932019, 336257744896, 8134269015601, 212309523595264, 5946914908771219, 177934946000306176, 5663754614516217601
(list; graph; listen)
|
|
|
OFFSET
|
0,3
|
|
|
COMMENT
|
It appears that all members are of the form 3k+1. - Ralf Stephan (ralf(AT)ark.in-berlin.de), Nov 12 2007
|
|
REFERENCES
|
R. Ehrenborg and M. A. Readdy, The r-cubical lattice and a generalization of the cd-index, European J. Combin. 17 (1996), no. 8, 709-725.
R. Ehrenborg and M. A. Readdy, Sheffer posets and r-signed permutations. Ann. Sci. Math. Quebec, 19 (1995), no. 2, 173-196.
|
|
FORMULA
|
E.g.f.: (1-sin 3x)^(-1/3).
|
|
CROSSREFS
|
Cf. A007863.
Sequence in context: A127060 A134147 A157303 this_sequence A067577 A155804 A126147
Adjacent sequences: A007785 A007786 A007787 this_sequence A007789 A007790 A007791
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
R. Ehrenborg and M. A. Readdy [ ehrenbor(AT)lacim.uqam.ca, readdy(AT)lacim.uqam.ca ].
|
|
|
Search completed in 0.002 seconds
|
