A330390 G.f.: (1 + 15*x) / (1 - 2*x - 17*x^2).

1, 17, 51, 391, 1649, 9945, 47923, 264911, 1344513, 7192513, 37241747, 196756215, 1026622129, 5398099913, 28248776019, 148265250559, 776759693441, 4074028646385, 21352972081267, 111964431151079, 586929387683697, 3077254104935737, 16132307800494323

Offset

0,2

Links

Colin Barker, Table of n, a(n) for n = 0..1000

Index entries for linear recurrences with constant coefficients, signature (2,17).

Formula

a(n) = 2*a(n-1) + 17*a(n-2) for n>1.

a(n)/a(n-1) ~ 1 + 3*sqrt(2).

a(n) = ((1 - 3*sqrt(2))^n*(-16+3*sqrt(2)) + (1+3*sqrt(2))^n*(16 + 3*sqrt(2))) / (6*sqrt(2)). - Colin Barker, Dec 14 2019

Mathematica

CoefficientList[Series[(1+15x)/(1-2x-17x^2), {x, 0, 30}], x] (* or *) LinearRecurrence[{2, 17}, {1, 17}, 30] (* Harvey P. Dale, Jul 31 2021 *)

Prog

(PARI) Vec((1 + 15*x) / (1 - 2*x - 17*x^2) + O(x^25)) \\ Colin Barker, Jan 25 2020

Crossrefs

Cf. A164544, A328606.

Sequence in context: A258598 A223906 A146673 * A078757 A041560 A195666

Adjacent sequences: A330387 A330388 A330389 * A330391 A330392 A330393

Keyword

nonn,easy

Author

Kyle MacLean Smith, Dec 13 2019

Status

approved