A056015 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), with a(0)=...=a(4)=0, a(5)=1.

0, 0, 0, 0, 0, 1, 6, 31, 152, 730, 3480, 16542, 78544, 372779, 1768958, 8393741, 39827472, 188975588, 896658432, 4254492236, 20186832928, 95783024581, 454473817254, 2156399264651, 10231739547432, 48547824776670, 230350985294584, 1092975362559562

Offset

0,7

Comments

With a(0)=0, a(1)=1, a(2)=1, a(3)=2, a(4)=4, a(5)=7, this recurrence produces a(n) = A000073(n+1) (tribonacci numbers).

Links

Table of n, a(n) for n=0..27.

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

Formula

O.g.f.: -x^5/((x^3+x^2-5*x+1)*(x^3+x^2+x-1)). - R. J. Mathar, Nov 23 2007

Crossrefs

Cf. A000073, A056014.

Sequence in context: A268401 A346226 A240879 * A128740 A227505 A026705

Adjacent sequences: A056012 A056013 A056014 * A056016 A056017 A056018

Keyword

nonn,easy

Author

Asher Auel, Jun 06 2000

Extensions

New name, from formula, added by Michel Marcus, Mar 19 2024

Status

approved