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A175015 y-values in the solution to x^2-57*y^2=1. 2
0, 20, 6040, 1824060, 550860080, 166357920100, 50239541010120, 15172175027136140, 4581946618654104160, 1383732706658512320180, 417882695464252066590200, 126199190297497465597920220 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
The corresponding values of x of this Pell equation are in A174759.
LINKS
FORMULA
a(n) = 302*a(n-1)-a(n-2) with a(1)=0, a(2)=20.
G.f.: 20*x^2/(1-302*x+x^2).
a(n) = ((151+20*sqrt(57))^(n-1) - (151-20*sqrt(57))^(n-1)) / (2*sqrt(57)). - Alan Michael Gómez Calderón, Oct 06 2023
MATHEMATICA
LinearRecurrence[{302, -1}, {0, 20}, 30]
PROG
(Magma) I:=[0, 20]; [n le 2 select I[n] else 302*Self(n-1)-Self(n-2): n in [1..20]];
CROSSREFS
Cf. A174759.
Sequence in context: A250020 A088852 A123379 * A135292 A222721 A223051
KEYWORD
nonn,easy
AUTHOR
Vincenzo Librandi, Apr 15 2010
STATUS
approved

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Last modified June 25 10:14 EDT 2024. Contains 373701 sequences. (Running on oeis4.)