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A158254
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a(n) = 289n^2 + 2n.
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2
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291, 1160, 2607, 4632, 7235, 10416, 14175, 18512, 23427, 28920, 34991, 41640, 48867, 56672, 65055, 74016, 83555, 93672, 104367, 115640, 127491, 139920, 152927, 166512, 180675, 195416, 210735, 226632, 243107, 260160, 277791, 296000, 314787
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OFFSET
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1,1
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COMMENTS
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The identity (289*n+1)^2-(289*n^2+2*n)*(17)^2=1 can be written as A158255(n)^2-a(n)*(17)^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).
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MATHEMATICA
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LinearRecurrence[{3, -3, 1}, {291, 1160, 2607}, 50]
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PROG
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(Magma) I:=[291, 1160, 2607]; [n le 3 select I[n] else 3*Self(n-1)-3*Self(n-2)+1*Self(n-3): n in [1..50]];
(PARI) a(n) = 289*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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