

A214831


a(n) = a(n1) + a(n2) + a(n3), with a(0) = 1, a(1) = a(2) = 9.


13



1, 9, 9, 19, 37, 65, 121, 223, 409, 753, 1385, 2547, 4685, 8617, 15849, 29151, 53617, 98617, 181385, 333619, 613621, 1128625, 2075865, 3818111, 7022601, 12916577, 23757289, 43696467, 80370333, 147824089, 271890889, 500085311, 919800289, 1691776489
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OFFSET

0,2


COMMENTS

Part of a group of sequences defined by a(0), a(1)=a(2), a(n)=a(n1)+a(n2)+a(n3) which is a subgroup of sequences with linear recurrences and constant coefficients listed in the index. See comments in A214727.


LINKS

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


FORMULA

G.f.: (x^28*x1)/(x^3+x^2+x1).


MATHEMATICA

LinearRecurrence[{1, 1, 1}, {1, 9, 9}, 40] (* Harvey P. Dale, Oct 11 2017 *)


PROG

(PARI) Vec((x^28*x1)/(x^3+x^2+x1) + O(x^40)) \\ Michel Marcus, Jul 08 2014


CROSSREFS

Cf. A000213, A000288, A000322, A000383, A060455, A136175, A141036, A141523, A214825A214831, A244930, A244931.
Sequence in context: A022092 A245430 A161365 * A197497 A053456 A144424
Adjacent sequences: A214828 A214829 A214830 * A214832 A214833 A214834


KEYWORD

nonn,easy


AUTHOR

Abel Amene, Aug 07 2012


STATUS

approved



