A120470 - OEIS

%I #10 Sep 06 2016 17:35:58

%S 7,34,124,520,2032,8224,32704,131200,524032,2097664,8387584,33556480,

%T 134213632,536879104,2147467264,8589967360,34359672832,137439084544,

%U 549755551744,2199023779840,8796091973632,35184374185984

%N 2*4^n +(-1)^n*2^(n-1).

%D Cotton and Wilkinson, Advanced Inorganic Chemistry, Interscience publishers, New York, 1966, page 664, figure 26-4

%H <a href="/index/Rec">Index entries for linear recurrences with constant coefficients</a>, signature (2,8).

%F G.f. -x*(7+20*x) / ( (2*x+1)*(4*x-1) ). - R. J. Mathar, Oct 30 2011

%t M = {{0, 1, 1, 1, 1, 0}, {1, 0, 1, 0, 1, 1}, {1, 1, 0, 1, 0, 1}, {1, 0, 1, 0, 1, 1}, {1, 1, 0, 1, 0, 1}, {0, 1, 1, 1, 1, 0}} v[1] = {0, 1, 1, 2, 3, 5} v[n_] := v[n] = M.v[n - 1] a = Table[Floor[v[n][[1]]], {n, 1, 50}] Det[M - x*IdentityMatrix[6]] Factor[%] aaa = Table[x /. NSolve[Det[M - x*IdentityMatrix[6]] == 0, x][[n]], {n, 1, 6}] Abs[aaa] a1 = Table[N[a[[n]]/a[[n - 1]]], {n, 7, 50}]

%t LinearRecurrence[{2,8},{7,34},30] (* _Harvey P. Dale_, Sep 06 2016 *)

%K nonn,easy

%O 1,1

%A _Roger L. Bagula_ and _Gary W. Adamson_, Jul 04 2006