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a(n) = (17 -3*(-1)^n)/2.
2

%I #24 Dec 14 2023 05:53:27

%S 7,10,7,10,7,10,7,10,7,10,7,10,7,10,7,10,7,10,7,10,7,10,7,10,7,10,7,

%T 10,7,10,7,10,7,10,7,10,7,10,7,10,7,10,7,10,7,10,7,10,7,10,7,10,7,10,

%U 7,10,7,10,7,10,7,10,7,10,7,10

%N a(n) = (17 -3*(-1)^n)/2.

%C Period 2.

%H <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (0,1).

%F G.f.: ( -7-10*x ) / ( (x-1)*(1+x) ). - _R. J. Mathar_, Nov 21 2011

%F a(n) = 7 + 2^(1 - (-1)^n) - 1. - _Vincenzo Librandi_, Feb 28 2020

%t PadRight[{},120,{7,10}] (* _Harvey P. Dale_, Jul 08 2019 *)

%o (Magma) &cat [[7, 10]^^50]; // _Vincenzo Librandi_, Feb 28 2020

%K nonn

%O 0,1

%A _N. J. A. Sloane_.