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A174746
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x-values in the solution to x^2-31*y^2=1.
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2
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1, 1520, 4620799, 14047227440, 42703566796801, 129818829015047600, 394649197502177907199, 1199733430587791822837360, 3647189234337689639247667201, 11087454072653145915521085453680
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OFFSET
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1,2
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COMMENTS
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The corresponding values of y of this Pell equation are in A174771.
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LINKS
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FORMULA
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a(n) = 3040*a(n-1)-a(n-2) with a(1)=1, a(2)=1520.
G.f.: x*(1-1520*x)/(1-3040*x+x^2).
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MATHEMATICA
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LinearRecurrence[{3040, -1}, {1, 1520}, 30]
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PROG
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(Magma) I:=[1, 1520]; [n le 2 select I[n] else 3040*Self(n-1)-Self(n-2): n in [1..20]];
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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STATUS
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approved
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