A108143 a(n)= 5*a(n-1) -a(n-2) -a(n-3).

1, 1, 1, 3, 13, 61, 289, 1371, 6505, 30865, 146449, 694875, 3297061, 15643981, 74227969, 352198803, 1671122065, 7929183553, 37622596897, 178512678867, 847011613885, 4018922793661, 19069089675553, 90479513970219

Offset: 0

Author

Roger L. Bagula, Jun 05 2005

Keywords

• nonn
• easy

References

• Roger Bagula, Factoring Double Fibonacci Sequences, 2000

Links

• Index entries for linear recurrences with constant coefficients, signature (5,-1,-1)

Crossrefs

Cf. A056015, A056016.

Programs

Mathematica

F[1] = 1; F[2] = 1; F[3] = 1; F[n__] := F[n] = 5*F[n - 1] - F[n - 2] - F[n - 3] a = Table[Abs[F[n]], {n, 1, 50}]
LinearRecurrence[{5,-1,-1},{1,1,1},30] (* Harvey P. Dale, Jan 21 2023 *)

Formula

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

Extensions

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