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A174776
y-values in the solution to x^2 - 39*y^2 = 1.
2
0, 4, 200, 9996, 499600, 24970004, 1248000600, 62375059996, 3117504999200, 155812874900004, 7787526240001000, 389220499125149996, 19453237430017498800, 972272651001749790004, 48594179312657472001400
OFFSET
1,2
COMMENTS
The corresponding values of x of this Pell equation are in A174751.
FORMULA
a(n) = 50*a(n-1)-a(n-2) with a(1)=0, a(2)=4.
G.f.: 4*x^2/(1-50*x+x^2).
MATHEMATICA
LinearRecurrence[{50, -1}, {0, 4}, 30]
PROG
(Magma) I:=[0, 4]; [n le 2 select I[n] else 50*Self(n-1)-Self(n-2): n in [1..20]];
CROSSREFS
Cf. A174751.
Sequence in context: A156235 A356214 A034862 * A216932 A317273 A049656
KEYWORD
nonn,easy
AUTHOR
Vincenzo Librandi, Apr 15 2010
STATUS
approved