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A330390
G.f.: (1 + 15*x) / (1 - 2*x - 17*x^2).
1
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
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
Sequence in context: A258598 A223906 A146673 * A078757 A041560 A195666
KEYWORD
nonn,easy
AUTHOR
Kyle MacLean Smith, Dec 13 2019
STATUS
approved