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A174749
x-values in the solution to x^2-34*y^2=1.
2
1, 35, 2449, 171395, 11995201, 839492675, 58752492049, 4111834950755, 287769694060801, 20139766749305315, 1409495902757311249, 98644573426262482115, 6903710643935616436801, 483161100502066888093955
OFFSET
1,2
COMMENTS
The corresponding values of y of this Pell equation are in A174773.
FORMULA
a(n) = 70*a(n-1)-a(n-2) with a(1)=1, a(2)=35.
G.f.: x*(1-35*x)/(1-70*x+x^2).
MATHEMATICA
Transpose[NestList[{#[[2]], 70#[[2]]-#[[1]]}&, {1, 35}, 20]][[1]] (* Harvey P. Dale, Mar 06 2011 *)
LinearRecurrence[{70, -1}, {1, 35}, 230] (* Vincenzo Librandi, Dec 20 2011 *)
PROG
(Magma) I:=[1, 35]; [n le 2 select I[n] else 70*Self(n-1)-Self(n-2): n in [1..20]];
CROSSREFS
Cf. A174773.
Sequence in context: A215291 A249886 A290584 * A184124 A343586 A201725
KEYWORD
nonn,easy
AUTHOR
Vincenzo Librandi, Apr 13 2010
STATUS
approved