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A122572 a(1)=a(2)=1, a(n) = -14a(n-1) - a(n-2). 1
1, 1, -15, 209, -2911, 40545, -564719, 7865521, -109552575, 1525870529, -21252634831, 296011017105, -4122901604639, 57424611447841, -799821658665135, 11140078609864049, -155161278879431551, 2161117825702177665, -30100488280951055759, 419245718107612602961 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

Characteristic polynomial associated with the elliptic cubic invariant x^8 + 14*x^4 + 1.

REFERENCES

Henry MacKean and Victor Moll, Elliptic Curves, Cambridge University Press, New York, 1997, page 22

LINKS

Indranil Ghosh, Table of n, a(n) for n = 1..874

Gareth Jones and David Singerman, Belyi Functions, Hypermaps and Galois Groups, Bull. London Math. Soc., 28 (1996), 561-590.

Tanya Khovanova, Recursive Sequences

Index entries for linear recurrences with constant coefficients, signature (-14,-1).

FORMULA

G.f.: x(1+15x)/(1+14x+x^2). - Philippe Deléham, Nov 16 2008 [Corrected by Richard Choulet, Nov 21 2008]

a(n) = (1/3)*sqrt(3)*[ -7+4*sqrt(3)]^n-(1/3)*sqrt(3)*[ -7-4*sqrt(3)]^n+(1/2)*[ -7-4*sqrt(3)]^n+(1 /2)*[ -7+4*sqrt(3)]^n. - Paolo P. Lava, Nov 19 2008

a(n) = ((3+2*sqrt(3))/6)*(-7+4*sqrt(3))^(n-1)+((3-2*sqrt(3))/6)*(-7-4*sqrt(3))^(n-1) (n>=1). - Richard Choulet, Nov 21 2008

a(n) = (-1)^n*A028230(n-1), n>1. - R. J. Mathar, Mar 19 2009

a(n) = b such that (-1)^(2*n-3)*Integral_{x=0..Pi/2} cos((2*n-3)*x)/(2+sin(x)) dx = c + b*(log(2)-log(3)). - Francesco Daddi, Aug 01 2011

MATHEMATICA

LinearRecurrence[{-14, -1}, {1, 1}, 30] (* Harvey P. Dale, Jul 30 2013 *)

CROSSREFS

Sequence in context: A239991 A274563 A028230 * A067560 A019553 A234249

Adjacent sequences:  A122569 A122570 A122571 * A122573 A122574 A122575

KEYWORD

sign,easy

AUTHOR

Roger L. Bagula, Sep 17 2006

EXTENSIONS

Edited by N. J. A. Sloane, Dec 04 2006

STATUS

approved

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Last modified November 23 20:23 EST 2017. Contains 295141 sequences.