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119, 480, 1083, 1928, 3015, 4344, 5915, 7728, 9783, 12080, 14619, 17400, 20423, 23688, 27195, 30944, 34935, 39168, 43643, 48360, 53319, 58520, 63963, 69648, 75575, 81744, 88155, 94808, 101703, 108840, 116219, 123840, 131703, 139808
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OFFSET
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1,1
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COMMENTS
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The identity (29282*n^2-484*n+1)^2-(121*n^2-2*n)*(2662*n-22)^2=1 can be written as A157610(n)^2-a(n)*A157609(n)^2=1.
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LINKS
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FORMULA
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a(n) = 3*a(n-1) -3*a(n-2) +a(n-3).
G.f: x*(-119-123*x)/(x-1)^3.
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MATHEMATICA
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LinearRecurrence[{3, -3, 1}, {119, 480, 1083}, 40]
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PROG
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(Magma) I:=[119, 480, 1083]; [n le 3 select I[n] else 3*Self(n-1)-3*Self(n-2)+1*Self(n-3): n in [1..40]];
(PARI) a(n) = 121*n^2-2*n.
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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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