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A228554 x-values in the solution to the Pell equation x^2 - 85*y^2 = -1. 2
378, 216041742, 123476065138818, 70571263317093720342, 40334158693601634671687178, 23052504391353119813669652619422, 13175382254784845233371524284127523858, 7530231623112168370599341126488007078134182 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

All terms are multiples of 378.

LINKS

Colin Barker, Table of n, a(n) for n = 1..150

Index entries for linear recurrences with constant coefficients, signature (571538,-1).

FORMULA

a(n) = 571538*a(n-1)-a(n-2).

G.f.: 378*x*(x+1) / (x^2-571538*x+1).

MATHEMATICA

LinearRecurrence[{571538, -1}, {378, 216041742}, 20] (* Harvey P. Dale, Jul 10 2019 *)

PROG

(PARI) Vec(378*x*(x+1)/(x^2-571538*x+1) + O(x^30))

CROSSREFS

Cf. A228555 gives the corresponding y-values.

Sequence in context: A171115 A328552 A225994 * A108385 A020369 A142207

Adjacent sequences:  A228551 A228552 A228553 * A228555 A228556 A228557

KEYWORD

nonn,easy

AUTHOR

Colin Barker, Aug 25 2013

STATUS

approved

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Last modified May 27 21:52 EDT 2020. Contains 334671 sequences. (Running on oeis4.)