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A107330 a(n) = 4*a(n-1)-a(n-2)-3*a(n-3)+a(n-4), n>5. 0
3, 3, 12, 41, 148, 517, 1809, 6316, 22052, 76982, 268737, 938126, 3274873, 11432137, 39908034, 139313506, 486324452, 1697692337, 5926412412, 20688297461, 72220024873, 252110257132, 880082523684, 3072248060446, 10724798971577 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

LINKS

Table of n, a(n) for n=0..24.

Index entries for linear recurrences with constant coefficients, signature (4, -1, -3, 1).

FORMULA

G.f.: (-3*x^2-5*x^3-2*x^4+x^5-3+9*x)/( (x-1) * (x^3-2*x^2-3*x+1)). [Sep 28 2009]

MATHEMATICA

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

Join[{3, 3}, LinearRecurrence[{4, -1, -3, 1}, {12, 41, 148, 517}, 40]] (* Harvey P. Dale, Jul 10 2012 *)

CROSSREFS

Sequence in context: A097342 A025236 A014432 * A076509 A206704 A020550

Adjacent sequences:  A107327 A107328 A107329 * A107331 A107332 A107333

KEYWORD

nonn,easy

AUTHOR

Roger L. Bagula, May 22 2005

EXTENSIONS

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

STATUS

approved

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Last modified September 20 13:45 EDT 2020. Contains 337264 sequences. (Running on oeis4.)