%I #15 Aug 08 2021 14:44:38

%S 7,33,85,189,397,813,1645,3309,6637,13293,26605,53229,106477,212973,

%T 425965,851949,1703917,3407853,6815725,13631469,27262957,54525933,

%U 109051885,218103789,436207597,872415213,1744830445,3489660909,6979321837,13958643693

%N a(n) = 13*2^(n+1) - 19.

%C Most terms in even positions of A278066 are terms in this sequence.

%H Harvey P. Dale, <a href="/A275163/b275163.txt">Table of n, a(n) for n = 0..1000</a>

%H <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (3,-2).

%F a(0) = 7; a(n) = 2*a(n-1) + 19 for n>=1.

%F G.f.: (12*x+7)/((1-2*x)*(1-x)).

%t NestList[2#+19&,7,30] (* or *) LinearRecurrence[{3,-2},{7,33},30] (* _Harvey P. Dale_, Aug 08 2021 *)

%Y Cf. A278066.

%K nonn

%O 0,1

%A _Nathan Fox_, Nov 13 2016