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A007788 Number of augmented Andre 3-signed permutations: E.g.f. (1-sin(3*x))^(-1/3). 8
1, 1, 4, 19, 136, 1201, 13024, 165619, 2425216, 40132801, 740882944, 15091932019, 336257744896, 8134269015601, 212309523595264, 5946914908771219, 177934946000306176, 5663754614516217601 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

COMMENTS

It appears that all members are of the form 3k+1. - Ralf Stephan, 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.

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 0..200

R. Ehrenborg and M. A. Readdy, Sheffer posets and r-signed permutations, Preprint submitted to Ann. Sci. Math. Quebec, 1994. (Annotated scanned copy)

FORMULA

E.g.f.: (1-sin(3*x))^(-1/3).

a(n) ~ n! * 2*6^n/(Pi^(n+2/3)*n^(1/3)*Gamma(2/3)). - Vaclav Kotesovec, Jun 25 2013

MATHEMATICA

With[{nn=20}, CoefficientList[Series[(1-Sin[3x])^(-1/3), {x, 0, nn}], x] Range[0, nn]!] (* Harvey P. Dale, Nov 23 2011 *)

CROSSREFS

Cf. A007863, A235135, A235132.

Sequence in context: A134147 A220066 A157303 * A259354 A215851 A197920

Adjacent sequences:  A007785 A007786 A007787 * A007789 A007790 A007791

KEYWORD

nonn

AUTHOR

R. Ehrenborg (ehrenbor(AT)lacim.uqam.ca) and M. A. Readdy (readdy(AT)lacim.uqam.ca)

STATUS

approved

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Last modified February 20 14:49 EST 2019. Contains 320327 sequences. (Running on oeis4.)