A122884 a(n+1) = 4*a(n) + 11*a(n-1) - 2*a(n-3).

1, 7, 39, 231, 1339, 7819, 45543, 265503, 1547347, 9018835, 52565151, 306373095, 1785671371, 10407659227, 60660275799, 353554011951, 2060663763139, 12010428632419, 70001907900303, 408001019031543, 2378004205764667

Offset

1,2

Links

Table of n, a(n) for n=1..21.

Index entries for linear recurrences with constant coefficients, signature (4,11,-2).

Formula

a(n+1) = 4*a(n) + 11*a(n-1) - 2*a(n-3).

G.f.: x*(1+3*x)/((2*x+1)* (1-6*x+x^2)).

Crossrefs

Cf. A122883, A122885, A122886.

Sequence in context: A287809 A155589 A071082 * A370228 A139173 A219437

Adjacent sequences: A122881 A122882 A122883 * A122885 A122886 A122887

Keyword

nonn,easy

Author

Gary W. Adamson and Roger L. Bagula, Sep 17 2006

Extensions

More terms from Paolo P. Lava, Jul 09 2008

Status

approved