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A097786 a(n) = 3*a(n-1) + C(n+3,3) for n > 0; a(0)=1. 4

%I #12 Sep 09 2023 10:35:08

%S 1,7,31,113,374,1178,3618,10974,33087,99481,298729,896551,2690108,

%T 8070884,24213332,72640812,217923405,653771355,1961315395,5883947725,

%U 17651844946,52955536862,158866612886,476599841258,1429799526699

%N a(n) = 3*a(n-1) + C(n+3,3) for n > 0; a(0)=1.

%C Partial sums of A052150.

%H <a href="/index/Rec#order_05">Index entries for linear recurrences with constant coefficients</a>, signature (7,-18,22,-13,3).

%F G.f.: 1/((1-3*x)*(1-x)^4);

%F a(n) = 3^(n+4)/16 - (4*n^3 + 42*n^2 + 152*n + 195)/48;

%F a(n) = Sum_{k=0..n} binomial(n+4, k+4)*2^k.

%F a(n) = 7*a(n-1) - 18*a(n-2) + 22*a(n-3) - 13*a(n-4) + 3*a(n-5); a(0) = 1, a(1)=7, a(2)=31, a(3)=113, a(4)=374. - _Harvey P. Dale_, Nov 26 2011

%t RecurrenceTable[{a[0]==1,a[n]==3a[n-1]+Binomial[n+3,3]},a,{n,30}] (* or *) LinearRecurrence[{7,-18,22,-13,3},{1,7,31,113,374},31] (* _Harvey P. Dale_, Nov 26 2011 *)

%K easy,nonn

%O 0,2

%A _Paul Barry_, Aug 24 2004

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Last modified April 19 03:16 EDT 2024. Contains 371782 sequences. (Running on oeis4.)