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A158306 324n - 1. 2
323, 647, 971, 1295, 1619, 1943, 2267, 2591, 2915, 3239, 3563, 3887, 4211, 4535, 4859, 5183, 5507, 5831, 6155, 6479, 6803, 7127, 7451, 7775, 8099, 8423, 8747, 9071, 9395, 9719, 10043, 10367, 10691, 11015, 11339, 11663, 11987, 12311, 12635, 12959 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

The identity (324*n-1)^2-(324*n^2-2*n)*(18)^2=1 can be written as a(n)^2-A158305(n)*(18)^2=1.

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..10000

Vincenzo Librandi, X^2-AY^2=1

E. J. Barbeau, Polynomial Excursions, Chapter 10: Diophantine equations (2010), pages 84-85 (row 15 in the first table at p. 85, case d(t) = t*(18^2*t-2)).

Index entries for linear recurrences with constant coefficients, signature (2,-1).

FORMULA

a(n) = 2*a(n-1)-a(n-2).

G.f.: x*(323+x)/(1-x)^2.

MATHEMATICA

324Range[50]-1  (* Harvey P. Dale, Mar 13 2011 *)

CROSSREFS

Cf. A158305.

Sequence in context: A177745 A065822 A279072 * A257973 A083138 A121209

Adjacent sequences:  A158303 A158304 A158305 * A158307 A158308 A158309

KEYWORD

nonn,easy

AUTHOR

Vincenzo Librandi, Mar 16 2009

STATUS

approved

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Last modified May 13 05:02 EDT 2021. Contains 343836 sequences. (Running on oeis4.)