A174765 y-values in the solution to x^2 - 19*y^2 = 1.

0, 39, 13260, 4508361, 1532829480, 521157514839, 177192022215780, 60244766395850361, 20483043382566906960, 6964174505306352516039, 2367798848760777288546300, 805044644404158971753225961

Offset

1,2

Comments

The corresponding values of x of this Pell equation are in A114048.

Links

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

Index entries for linear recurrences with constant coefficients, signature (340,-1).

Formula

a(n) = 340*a(n-1)-a(n-2) with a(1)=0, a(2)=39.

G.f.: 39*x^2/(1-340*x+x^2).

Mathematica

LinearRecurrence[{340, -1}, {0, 39}, 30]

Prog

(Magma) I:=[0, 39]; [n le 2 select I[n] else 340*Self(n-1)-Self(n-2): n in [1..20]];

Crossrefs

Cf. A114048.

Sequence in context: A279116 A266307 A210327 * A115462 A268072 A268422

Adjacent sequences: A174762 A174763 A174764 * A174766 A174767 A174768

Keyword

nonn,easy

Author

Vincenzo Librandi, Apr 14 2010

Status

approved