



2, 2, 5, 9, 19, 40, 88, 198, 455, 1061, 2501, 5940, 14182, 33982, 81625, 196389, 473039, 1140260, 2749988, 6634458, 16009555, 38638441, 93261961, 225122760, 543443402, 1311905882, 3167087405, 7645809249, 18458266699, 44561632000
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OFFSET

0,1


LINKS

Vincenzo Librandi, Table of n, a(n) for n = 0..1000
Index entries for linear recurrences with constant coefficients, signature (3,0,3,1).


FORMULA

a(n) = 3*a(n1)3*a(n3)a(n4). G.f.: (24*xx^2)/((1xx^2)*(12*xx^2)). [Colin Barker, Jun 22 2012]
a(n) = A000129(n) + A000032(n). [Jonathan Vos Post, Sep 02 2013]


EXAMPLE

18+70 = 88.


MAPLE

gfpell := x/(12*xx^2): gfluc := (2x)/(1xx^2): s := series(gfpell+gfluc, x, 100): for i from 0 to 60 do printf(`%d, `, coeff(s, x, i)) od:


MATHEMATICA

LinearRecurrence[{3, 0, 3, 1}, {2, 2, 5, 9}, 30] (* Harvey P. Dale, Jun 05 2017 *)


PROG

(MAGMA) I:=[2, 2, 5, 9]; [n le 4 select I[n] else 3*Self(n1)3*Self(n3)Self(n4): n in [1..30]]; // Vincenzo Librandi, Juan 07 2017


CROSSREFS

Cf. A000032, A000129, A001932, A226638 Product of Pell and Lucas numbers.
Sequence in context: A302483 A052969 A002990 * A326493 A003228 A184713
Adjacent sequences: A060402 A060403 A060404 * A060406 A060407 A060408


KEYWORD

nonn,easy


AUTHOR

N. J. A. Sloane, Apr 05 2001


EXTENSIONS

More terms from James A. Sellers, Apr 06 2001


STATUS

approved



