A147677 - OEIS

%I #19 Jan 29 2024 00:42:38

%S 7,2,10,5,13,8,16,11,19,14,22,17,25,20,28,23,31,26,34,29,37,32,40,35,

%T 43,38,46,41,49,44,52,47,55,50,58,53,61,56,64,59,67,62,70,65,73,68,76,

%U 71,79,74,82,77,85,80,88,83,91,86,94,89,97,92,100,95,103,98,106,101,109

%N Subtract 5, add 8, repeat.

%C A147675-A147678 are from a quiz that someone asked me to help them with.

%H <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (1,1,-1).

%F From _Zak Seidov_, Apr 22 2009: (Start)

%F a(n) = a(n-2) + 3.

%F a(n) = (1/4)*(6*n + 9 - 13*(-1)^n). (End)

%F From _R. J. Mathar_, Apr 22 2009: (Start)

%F a(n) = a(n-1) + a(n-2) - a(n-3) = 3*n/2 + 9/4 + 13*(-1)^(n+1)/4.

%F G.f.: x*(7-5*x+x^2)/((1+x)*(x-1)^2). (End)

%t LinearRecurrence[{1,1,-1},{7,2,10},80] (* _Harvey P. Dale_, Jan 16 2015 *)

%K nonn,easy

%O 1,1

%A _N. J. A. Sloane_, Apr 21 2009

%E More terms from _Zak Seidov_ and _R. J. Mathar_, Apr 22 2009