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a(0)=1, a(1)=7, a(n)=14*a(n-1)-7*a(n-2) for n>1 .
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%I #13 Jan 03 2024 23:53:14

%S 1,7,91,1225,16513,222607,3000907,40454449,545355937,7351801975,

%T 99107736091,1336045691449,18010885527649,242800077546943,

%U 3273124886963659,44124147874662625,594826196036531137,8018697709388797543,108097984559187447643,1457240899862902684201

%N a(0)=1, a(1)=7, a(n)=14*a(n-1)-7*a(n-2) for n>1 .

%H Harvey P. Dale, <a href="/A165230/b165230.txt">Table of n, a(n) for n = 0..885</a>

%H <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (14,-7).

%F G.f.: (1-7*x)/(1-14*x+7*x^2) .

%F a(n) = (1/2)*((7+sqrt(42))^n+(7-sqrt(42))^n). [_Paolo P. Lava_, Sep 16 2009]

%t LinearRecurrence[{14,-7},{1,7},20] (* _Harvey P. Dale_, Dec 18 2016 *)

%K nonn,easy

%O 0,2

%A _Philippe Deléham_, Sep 09 2009

%E More terms from _Harvey P. Dale_, Dec 18 2016