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a(n) = 4*a(n-1)-3*a(n-2) -3*a(n-3) +2*a(n-4) + a(n-5), n>7.
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%I #7 Dec 17 2017 13:05:53

%S 4,3,9,17,40,92,215,506,1200,2861,6848,16436,39523,95162,229328,

%T 552977,1333920,3218612,7767575,18747986,45254200,109241261,263712248,

%U 636626156,1536900483,3710323442

%N a(n) = 4*a(n-1)-3*a(n-2) -3*a(n-3) +2*a(n-4) + a(n-5), n>7.

%H <a href="/index/Rec#order_05">Index entries for linear recurrences with constant coefficients</a>, signature (4,-3,-3,2,1).

%F G.f.: (-2*x^3+3*x^6+x^7-9*x^2+13*x-4)/((x-1)* (x^2+x-1) * (x^2+2*x-1) ). [Sep 28 2009]

%F a(n) = 1+A000032(n) + A002203(n), n>2 [Sep 28 2009].

%t n = 3; b4 = x /. NSolve[x^4 - n*x^3 + n*x + 1 == 0, x][[4]] b3 = x /. NSolve[x^4 - n*x^3 + n*x + 1 == 0, x][[3]] b2 = x /. NSolve[x^4 - n*x^3 + n*x + 1 == 0, x][[2]] b1 = x /. NSolve[x^4 - n*x^3 + n*x + 1 == 0, x][[1]] digits = 25 a = Table[n*(b4^m + b3^m + b1^m + b2^m)/ (b4 + b3 + b2 + b1), {n, 0, digits}]

%K nonn,easy

%O 0,1

%A _Roger L. Bagula_, May 24 2005

%E Definition replaced by recurrence by the Associate Editors of the OEIS, Sep 28 2009