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A175014
y-values in the solution to x^2-55*y^2=1.
2
0, 12, 2136, 380196, 67672752, 12045369660, 2144008126728, 381621401187924, 67926465403323744, 12090529220390438508, 2152046274764094730680, 383052146378788471622532, 68181130009149583854080016
OFFSET
1,2
COMMENTS
The corresponding values of x of this Pell equation are in A174758.
FORMULA
a(n) = 178*a(n-1)-a(n-2) with a(1)=0, a(2)=12.
G.f.: 12*x^2/(1-178*x+x^2).
a(n) = ((89+12*sqrt(55))^(n-1) - (89-12*sqrt(55))^(n-1))/(2*sqrt(55)). - Alan Michael Gómez Calderón, Oct 06 2023
MATHEMATICA
LinearRecurrence[{178, -1}, {0, 12}, 30]
PROG
(Magma) I:=[0, 12]; [n le 2 select I[n] else 178*Self(n-1)-Self(n-2): n in [1..20]];
CROSSREFS
Cf. A174758.
Sequence in context: A342964 A009063 A012675 * A101812 A064074 A005249
KEYWORD
nonn,easy
AUTHOR
Vincenzo Librandi, Apr 15 2010
STATUS
approved