%I #13 Sep 08 2022 08:46:00
%S 2,11,74,515,3602,25211,176474,1235315,8647202,60530411,423712874,
%T 2965990115,20761930802,145333515611,1017334609274,7121342264915,
%U 49849395854402,348945770980811,2442620396865674,17098342778059715
%N (3*7^n+1)/2.
%H Vincenzo Librandi, <a href="/A199417/b199417.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 (8,7).
%F a(n) = 7*a(n1)3.
%F a(n) = 8*a(n1)7*a(n2).
%F G.f.: (25*x)/((1x)*(17*x)).
%t (3*7^Range[0,30]+1)/2 (* or *) LinearRecurrence[{8,7},{2,11},30] (* _Harvey P. Dale_, Nov 20 2012 *)
%o (Magma) [(3*7^n+1)/2: n in [0..30]];
%K nonn,easy
%O 0,1
%A _Vincenzo Librandi_, Nov 06 2011
