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A157441
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a(n) = 1331*n - 1122.
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3
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209, 1540, 2871, 4202, 5533, 6864, 8195, 9526, 10857, 12188, 13519, 14850, 16181, 17512, 18843, 20174, 21505, 22836, 24167, 25498, 26829, 28160, 29491, 30822, 32153, 33484, 34815, 36146, 37477, 38808, 40139, 41470, 42801, 44132, 45463
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OFFSET
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1,1
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COMMENTS
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The identity (14641*n^2 - 24684*n + 10405)^2 - (121*n^2 - 204*n + 86)*(1331*n - 1122)^2 = 1 can be written as A157442(n)^2 - A157440(n)*a(n)^2 = 1. - Vincenzo Librandi, Jan 29 2012
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LINKS
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FORMULA
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MATHEMATICA
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PROG
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(Magma) I:=[209, 1540]; [n le 2 select I[n] else 2*Self(n-1)-Self(n-2): n in [1..50]]; // Vincenzo Librandi, Jan 29 2012
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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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