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 A051405 a(n) = (3^n+1)*(3^(n+1)+1)/4. 0

%I #11 Mar 06 2018 19:18:54

%S 2,10,70,574,5002,44530,399310,3589414,32291602,290585050,2615147350,

%T 23535971854,211822683802,1906400965570,17157599124190,

%U 154418363419894,1389765184685602,12507886403890090,112570976860169830,1013138789417005534

%N a(n) = (3^n+1)*(3^(n+1)+1)/4.

%H <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (13, -39, 27).

%F a(0)=2, a(1)=10, a(2)=70, a(n)=13*a(n-1)-39*a(n-2)+27*a(n-3). - _Harvey P. Dale_, Jul 13 2012

%F G.f.: ( -2+16*x-18*x^2 ) / ( (x-1)*(3*x-1)*(9*x-1) ). - _R. J. Mathar_, Nov 07 2015

%F a(n) = 2*A051406(n). - _R. J. Mathar_, Nov 07 2015

%t Table[(3^n+1)(3^(n+1)+1)/4,{n,0,20}] (* or *) LinearRecurrence[{13,-39,27},{2,10,70},20] (* _Harvey P. Dale_, Jul 13 2012 *)

%K nonn,easy

%O 0,1

%A _Colin Mallows_

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Last modified May 19 00:35 EDT 2024. Contains 372666 sequences. (Running on oeis4.)