A120470 2*4^n +(-1)^n*2^(n-1).

7, 34, 124, 520, 2032, 8224, 32704, 131200, 524032, 2097664, 8387584, 33556480, 134213632, 536879104, 2147467264, 8589967360, 34359672832, 137439084544, 549755551744, 2199023779840, 8796091973632, 35184374185984

Offset

1,1

References

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

Links

Table of n, a(n) for n=1..22.

Index entries for linear recurrences with constant coefficients, signature (2,8).

Formula

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

Mathematica

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}]
LinearRecurrence[{2, 8}, {7, 34}, 30] (* Harvey P. Dale, Sep 06 2016 *)

Crossrefs

Sequence in context: A201230 A071598 A224036 * A036423 A147827 A036632

Adjacent sequences: A120467 A120468 A120469 * A120471 A120472 A120473

Keyword

nonn,easy

Author

Roger L. Bagula and Gary W. Adamson, Jul 04 2006

Status

approved