

A292545


Number of 6cycles in the nSierpinski tetrahedron graph.


3



0, 218, 876, 3504, 14016, 56064, 224256, 897024, 3588096, 14352384, 57409536, 229638144, 918552576, 3674210304, 14696841216, 58787364864, 235149459456, 940597837824, 3762391351296, 15049565405184, 60198261620736, 240793046482944, 963172185931776, 3852688743727104
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OFFSET

1,2


LINKS



FORMULA

a(n) = 219*4^(n  2) for n > 2.
a(n) = 4*a(n1) for n > 2.
G.f.: 2*x^2*(109 + 2*x)/(1 + 4*x).


MATHEMATICA

Table[Piecewise[{{0, n == 1}, {218, n == 2}}, 219 4^(n  2)], {n, 20}]
Join[{0, 218}, LinearRecurrence[{4}, {876}, 20]]
CoefficientList[Series[2 x (109 + 2 x)/(1 + 4 x), {x, 0, 20}], x]


PROG

(PARI) concat(0, Vec(2*x^2*(109 + 2*x)/(1 + 4*x) + O(x^50))) \\ Michel Marcus, Sep 19 2017


CROSSREFS



KEYWORD

nonn,easy


AUTHOR



STATUS

approved



