A056016 a(n) = -2*a(n - 1) -a(n - 2) -a(n - 3), a(0) = a(1) = a(2) = 1.

1, 1, 1, -4, 6, -9, 16, -29, 51, -89, 156, -274, 481, -844, 1481, -2599, 4561, -8004, 14046, -24649, 43256, -75909, 133211, -233769, 410236, -719914, 1263361, -2217044, 3890641, -6827599, 11981601, -21026244, 36898486, -64752329, 113632416, -199410989, 349941891, -614105209

Offset

0,4

Links

Table of n, a(n) for n=0..37.

Roger L. Bagula, Factoring Double Fibonacci Sequences, 2000 [Wayback Machine link from Felix Fröhlich, Nov 21 2019]

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

Formula

O.g.f.: (1+3x+4x^2)/(1+2x+x^2+x^3). - R. J. Mathar, Aug 22 2008

Mathematica

LinearRecurrence[{-2, -1, -1}, {1, 1, 1}, 40] (* Harvey P. Dale, Jun 09 2016 *)

Prog

(Magma) [n le 3 select 1 else -2*Self(n-1)-Self(n-2)-Self(n-3):n in [1..37]]; // Marius A. Burtea, Nov 21 2019

Crossrefs

Sequence in context: A225377 A036667 A371843 * A231997 A220144 A346591

Adjacent sequences: A056013 A056014 A056015 * A056017 A056018 A056019

Keyword

sign

Author

Asher Auel, Jun 06 2000

Extensions

Inserted a(0) and a(1) by R. J. Mathar, Aug 23 2008

Status

approved