A176375 x-values in the solution to x^2-69*y^2=1

1, 7775, 120901249, 1880014414175, 29234224019520001, 454592181623521601375, 7068908395011536881861249, 109921525087837216889420820575, 1709279708046960327618956878080001

Offset

1,2

Comments

The corresponding values of y of this Pell equation are in A176376.

Links

Vincenzo Librandi, Table of n, a(n) for n = 1..200

Index entries for linear recurrences with constant coefficients, signature (15550,-1).

Formula

a(n) = 15550*a(n-1)-a(n-2) with a(1)=1, a(2)=7775.

G.f.: x*(1-7775*x)/(1-15550*x+x^2).

Mathematica

LinearRecurrence[{15550, -1}, {1, 7775}, 30]

Prog

(Magma) I:=[1, 7775]; [n le 2 select I[n] else 15550*Self(n-1)-Self(n-2): n in [1..20]];

Crossrefs

Cf. A176376.

Sequence in context: A028538 A354976 A123990 * A210116 A223509 A187355

Adjacent sequences: A176372 A176373 A176374 * A176376 A176377 A176378

Keyword

nonn,easy

Author

Vincenzo Librandi, Apr 16 2010

Status

approved