A174766 y-values in the solution to x^2 - 22*y^2 = 1.

0, 42, 16548, 6519870, 2568812232, 1012105499538, 398766998005740, 157113185108762022, 61902196165854230928, 24389308176161458223610, 9609325519211448685871412, 3786049865261134620775112718

Offset

1,2

Comments

The corresponding values of x of this Pell equation are in A114050.

Links

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

Index entries for linear recurrences with constant coefficients, signature (394,-1).

Formula

a(n) = 394*a(n-1)-a(n-2) with a(1)=0, a(2)=42.

G.f.: 42*x^2/(1-394*x+x^2).

Mathematica

LinearRecurrence[{394, -1}, {0, 42}, 30]

Prog

(Magma) I:=[0, 42]; [n le 2 select I[n] else 394*Self(n-1)-Self(n-2): n in [1..20]];

Crossrefs

Cf. A114050.

Sequence in context: A268552 A227493 A095423 * A265191 A184895 A263058

Adjacent sequences: A174763 A174764 A174765 * A174767 A174768 A174769

Keyword

nonn,easy

Author

Vincenzo Librandi, Apr 14 2010

Status

approved