

A097632


2^n * Lucas(n).


0



2, 12, 64, 672, 8448, 138240, 2672640, 60641280, 1568931840, 45705461760, 1478924697600, 52646746521600, 2044394156851200, 86005817907609600, 3896481847600742400, 189139342470414336000, 9793081532749971456000
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OFFSET

1,1


COMMENTS

Number of possible wellcolored cycles on n nodes. Wellcolored means, each green vertex has at least a red child, each red vertex has no red child.


LINKS



FORMULA

E.g.f.: log(12x4x^2). Contrary to b(n) = 2^n*Fib(n), there seems to be no rational o.g.f. for the sequence.


CROSSREFS



KEYWORD

nonn


AUTHOR



STATUS

approved



