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440, 881, 1322, 1763, 2204, 2645, 3086, 3527, 3968, 4409, 4850, 5291, 5732, 6173, 6614, 7055, 7496, 7937, 8378, 8819, 9260, 9701, 10142, 10583, 11024, 11465, 11906, 12347, 12788, 13229, 13670, 14111, 14552, 14993, 15434, 15875, 16316, 16757
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OFFSET
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1,1
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COMMENTS
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The identity (441*n-1)^2-(441*n^2-2*n)*(21)^2=1 can be written as a(n)^2-A157737(n)*(21)^2=1.
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LINKS
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FORMULA
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a(n) = 2*a(n-1)-a(n-2).
G.f.: x*(440+x)/(1-x)^2.
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MATHEMATICA
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LinearRecurrence[{2, -1}, {440, 881}, 50]
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PROG
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(Magma) I:=[440, 881]; [n le 2 select I[n] else 2*Self(n-1)-Self(n-2): n in [1..50]];
(PARI) a(n) = 441*n - 1.
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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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