

A108146


a(n)= 4*a(n1) a(n2) a(n3).


0



1, 1, 1, 2, 6, 21, 76, 277, 1011, 3691, 13476, 49202, 179641, 655886, 2394701, 8743277, 31922521, 116552106, 425542626, 1553695877, 5672688776, 20711516601, 75619681751, 276094521627, 1008046888156, 3680473349246, 13437751987201
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OFFSET

0,4


LINKS

Table of n, a(n) for n=0..26.


FORMULA

G.f.: (13*x2*x^2)/(14*x+x^2+x^3). [Sep 28 2009]


MATHEMATICA

p = Expand[(x^3  x^2  x  1)*(x^3  4*x^2 + x + 1)] v[0] = {1, 1, 1}; M = {{0, 1, 0}, {0, 0, 1}, {1, 1, 4}}; Det[M  x*IdentityMatrix[3]] NSolve[Det[M  x*IdentityMatrix[3]] == 0, x] v[n_] := v[n] = M.v[n  1] a = Table[v[n][[1]], {n, 0, 50}]


CROSSREFS

Sequence in context: A116819 A116782 A112091 * A116798 A116821 A116772
Adjacent sequences: A108143 A108144 A108145 * A108147 A108148 A108149


KEYWORD

nonn,easy


AUTHOR

Roger L. Bagula, Jun 05 2005


EXTENSIONS

Definition replaced by recurrence by the Associate Editors of the OEIS, Sep 28 2009


STATUS

approved



