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A165510 a(0)=1, a(1)=9, a(n) = 72*a(n-2) - a(n-1). 2
1, 9, 63, 585, 3951, 38169, 246303, 2501865, 15231951, 164902329, 931798143, 10941169545, 56148296751, 731615910489, 3311061455583, 49365284099625, 189031140702351, 3365269314470649, 10244972816098623, 232054417825788105 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

a(n)/a(n-1) tends to -9.

First term < 0: a(27) = -60053864762402471338497.

LINKS

Harvey P. Dale, Table of n, a(n) for n = 0..1000

Index entries for linear recurrences with constant coefficients, signature (-1, 72).

FORMULA

G.f.: (1+10*x)/(1+x-72*x^2).

a(n) = Sum_{k=0..n} A112555(n,k)*8^k.

a(n) = (18*8^n-(-9)^n)/17. - Klaus Brockhaus, Sep 26 2009

E.g.f.: (18*exp(8*x) - exp(-9*x))/17. - G. C. Greubel, Oct 21 2018

MATHEMATICA

LinearRecurrence[{-1, 72}, {1, 9}, 30] (* Harvey P. Dale, Oct 15 2012 *)

PROG

(PARI) vector(30, n, n--; (18*8^n-(-9)^n)/17) \\ G. C. Greubel, Oct 21 2018

(MAGMA) [(18*8^n-(-9)^n)/17: n in [0..30]]; // G. C. Greubel, Oct 21 2018

CROSSREFS

Sequence in context: A206816 A336670 A065025 * A165749 A251211 A342197

Adjacent sequences:  A165507 A165508 A165509 * A165511 A165512 A165513

KEYWORD

sign

AUTHOR

Philippe Deléham, Sep 21 2009

STATUS

approved

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Last modified July 29 22:13 EDT 2021. Contains 346346 sequences. (Running on oeis4.)