A108142 a[1] = 1; a[2] = 1; a[3] = 1; a[4] = 1; a[5] = 1; a[6] = 1; for n >= 7, a[n] = 6*a[n - 1] - 5*a[n - 2] - 4*a[n - 3] - 3*a[ n - 4] + 2*a[n - 5] + a[n - 6]; then take absolute values.

1, 1, 1, 1, 1, 1, 3, 27, 151, 759, 3679, 17599, 83767, 397943, 1889059, 8964891, 42539855, 201849743, 957752095, 4544385823, 21562354767, 102309686479, 485441784803, 2303337053819, 10928934112423, 51855892302151

Offset: 1

Author

Roger L. Bagula, Jun 05 2005

Keywords

• nonn

Comments

The 2nd countdown sequence.

References

• Roger Bagula, Factoring Double Fibonacci Sequences, 2000

Links

• Index entries for linear recurrences with constant coefficients, signature (6, -5, -4, -3, 2, 1).

Crossrefs

Cf. A056015, A056016.

Programs

Mathematica

F[1] = 1; F[2] = 1; F[3] = 1; F[4] = 1; F[5] = 1; F[6] = 1; F[n__] := F[n] = 6*F[n - 1] - 5*F[n - 2] - 4*F[n - 3] - 3*F[ n - 4] + 2*F[n - 5] + F[n - 6] a = Table[Abs[F[n]], {n, 1, 50}]
LinearRecurrence[{6,-5,-4,-3,2,1},{1,1,1,1,1,1,3,27,151,759,3679,17599},30] (* Harvey P. Dale, Apr 25 2018 *)

Extensions

Edited by N. J. A. Sloane, Jun 08 2007