OFFSET
1,2
COMMENTS
The corresponding values of x of this Pell equation are in A056771.
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..200
Hacène Belbachir, Soumeya Merwa Tebtoub, and László Németh, Ellipse Chains and Associated Sequences, J. Int. Seq., Vol. 23 (2020), Article 20.8.5.
Index entries for linear recurrences with constant coefficients, signature (34,-1).
FORMULA
a(n) = 34*a(n-1)-a(n-2) with a(1)=0, a(2)=4.
G.f.: 4*x^2/(1-34*x+x^2).
a(n) = (1/3)*A001542(2n-2). - Bruno Berselli, Dec 19 2011
MATHEMATICA
LinearRecurrence[{34, -1}, {0, 4}, 30]
PROG
(Magma) I:=[0, 4]; [n le 2 select I[n] else 34*Self(n-1)-Self(n-2): n in [1..20]];
(Maxima) makelist(expand(((3+2*sqrt(2))^(2*n-2)-(3-2*sqrt(2))^(2*n-2))/(6*sqrt(2))), n, 1, 16); /* _Bruno Berselli, Dec 19 2011 */
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Vincenzo Librandi, Dec 18 2011
STATUS
approved