A174758 x-values in the solution to x^2-55*y^2=1.

1, 89, 15841, 2819609, 501874561, 89330852249, 15900389825761, 2830180058133209, 503756149957885441, 89665764512445475289, 15960002327065336716001, 2840790748453117489972889

Offset

1,2

Comments

The corresponding values of y of this Pell equation are in A175014.

Links

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

Index entries for linear recurrences with constant coefficients, signature (178,-1).

Formula

a(n) = 178*a(n-1)-a(n-2) with a(1)=1, a(2)=89.

G.f.: x*(1-89*x)/(1-178*x+x^2).

Mathematica

LinearRecurrence[{178, -1}, {1, 89}, 30]

Prog

(Magma) I:=[1, 89]; [n le 2 select I[n] else 178*Self(n-1)-Self(n-2): n in [1..20]];

Crossrefs

Cf. A175014.

Sequence in context: A116254 A086695 A056568 * A181681 A167398 A023330

Adjacent sequences: A174755 A174756 A174757 * A174759 A174760 A174761

Keyword

nonn,easy

Author

Vincenzo Librandi, Apr 13 2010

Status

approved