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G.f.: 1/((1-6*x)*(1-9*x)*(1-12*x)).
0

%I #20 Mar 11 2020 05:18:44

%S 1,27,495,7695,109431,1474767,19198215,244167615,3055792311,

%T 37811613807,464078786535,5662363023135,68791291322391,

%U 833094971965647,10065613312624455,121404092777808255,1462402531680439671

%N G.f.: 1/((1-6*x)*(1-9*x)*(1-12*x)).

%H <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (27,-234,648).

%F a(n) = (12^(n+2) - 2*9^(n+2) + 6^(n+2))/18. - _Yahia Kahloune_, Jun 30 2013

%F a(n) = 27*a(n-1) - 234*a(n-2) + 648*a(n-3). - _Jinyuan Wang_, Mar 10 2020

%o (PARI) Vec(1/((1-6*x)*(1-9*x)*(1-12*x)) + O(x^30)) \\ _Jinyuan Wang_, Mar 10 2020

%Y Cf. A017933.

%K nonn

%O 0,2

%A _N. J. A. Sloane_