A176380 x-values in the solution to x^2-71*y^2=1.

1, 3480, 24220799, 168576757560, 1173294208396801, 8166127521864977400, 56836246378886034307199, 395580266630919276913127640, 2753238598914951788429334067201

Offset

1,2

Comments

The corresponding values of y of this Pell equation are in A176381.

Links

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

Index entries for linear recurrences with constant coefficients, signature (6960,-1).

Formula

a(n) = 6960*a(n-1)-a(n-2) with a(1)=1, a(2)=3480.

G.f.: x*(1-3480*x)/(1-6960*x+x^2).

Mathematica

LinearRecurrence[{6960, -1}, {1, 3480}, 30]

Prog

(Magma) I:=[1, 3480]; [n le 2 select I[n] else 6960*Self(n-1)-Self(n-2): n in [1..20]];

Crossrefs

Cf. A176381.

Sequence in context: A232889 A328817 A159215 * A156773 A174753 A031557

Adjacent sequences: A176377 A176378 A176379 * A176381 A176382 A176383

Keyword

nonn,easy

Author

Vincenzo Librandi, Apr 16 2010

Status

approved