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A078486 Number of irreducible indecomposable pop-stack permutations of a certain type. +0
1
0, 1, 2, 6, 24, 102, 414, 1598, 5982, 22102, 81442, 300562, 1111638, 4117382, 15259738, 56561346, 209629750, 776850166, 2878660394, 10666717442, 39524757670, 146456879830, 542691221946, 2010931777154, 7451478924278, 27611353095414, 102313463160906 (list; graph; listen)
OFFSET

0,3

REFERENCES

M. D. Atkinson and T. Stitt, Restricted permutations and the wreath product, Discrete Math., 259 (2002), 19-36.

FORMULA

G.f.: (x-7*x^2+19*x^3-21*x^4+10*x^5-6*x^6)/(1-9*x+31*x^2-53*x^3+44*x^4-16*x^5+6*x^6).

CROSSREFS

Sequence in context: A150299 A094012 A141253 this_sequence A129817 A128652 A152316

Adjacent sequences: A078483 A078484 A078485 this_sequence A078487 A078488 A078489

KEYWORD

nonn

AUTHOR

N. J. A. Sloane (njas(AT)research.att.com), Jan 04 2003

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Last modified December 5 23:38 EST 2009. Contains 170428 sequences.


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