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A165506 a(0) = 1, a(1) = 8, a(n) = 56*a(n-2) - a(n-1). 2
1, 8, 48, 400, 2288, 20112, 108016, 1018256, 5030640, 51991696, 229724144, 2681810832, 10182741232, 139998665360, 430234843632, 7409690416528, 16683460826864, 398259202498704, 536014603805680, 21766500736121744 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

a(n)/a(n-1) tends to -8.

LINKS

G. C. Greubel, Table of n, a(n) for n = 0..1000

FORMULA

G.f.: (1+9*x)/(1+x-56*x^2).

a(n) = Sum_{k=0..n} A112555(n,k)*7^k.

a(n) = (16*7^n-(-8)^n)/15. - Klaus Brockhaus, Sep 26 2009

E.g.f.: (16*exp(7*x) - exp(-8*x))/15. - G. C. Greubel, Oct 21 2018

EXAMPLE

a(20)=8250317076996336, a(21)=1210673724145821328, a(22)=-748655967834026512, a(23)=68546384520000020880, a(24)=-110471118718705505552,...

MATHEMATICA

LinearRecurrence[{-1, 56}, {1, 8}, 50] (* G. C. Greubel, Oct 21 2018 *)

PROG

(PARI) vector(50, n, n--; (16*7^n-(-8)^n)/15) \\ G. C. Greubel, Oct 21 2018

(MAGMA) [(16*7^n-(-8)^n)/15: n in [0..50]]; // G. C. Greubel, Oct 21 2018

CROSSREFS

Sequence in context: A165041 A165049 A013186 * A165748 A220174 A239888

Adjacent sequences:  A165503 A165504 A165505 * A165507 A165508 A165509

KEYWORD

sign

AUTHOR

Philippe Deléham, Sep 21 2009

STATUS

approved

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Last modified May 16 12:21 EDT 2021. Contains 343942 sequences. (Running on oeis4.)