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A157660
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a(n) = 8000*n - 40.
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3
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7960, 15960, 23960, 31960, 39960, 47960, 55960, 63960, 71960, 79960, 87960, 95960, 103960, 111960, 119960, 127960, 135960, 143960, 151960, 159960, 167960, 175960, 183960, 191960, 199960, 207960, 215960, 223960, 231960, 239960, 247960, 255960
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OFFSET
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1,1
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COMMENTS
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The identity (80000*n^2 - 800*n + 1)^2 - (100*n^2 - n)*(8000*n - 40)^2 = 1 can be written as A157661(n)^2 - A157659(n)*a(n)^2 = 1 (see also the second part of the comment at A157661). - Vincenzo Librandi, Jan 28 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:=[7960, 15960]; [n le 2 select I[n] else 2*Self(n-1)-Self(n-2): n in [1..50]]; // Vincenzo Librandi, Jan 28 2012
(Sage) [40*(200*n - 1) for n in (1..40)] # G. C. Greubel, Nov 17 2018
(GAP) List([1..40], n -> 40*(200*n - 1)); # G. C. Greubel, Nov 17 2018
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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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