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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
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| 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 in A157661). - Vincenzo Librandi, Jan 28 2012
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LINKS
| Vincenzo Librandi, Table of n, a(n) for n = 1..10000
Vincenzo Librandi, X^2-AY^2=1
Index to sequences with linear recurrences with constant coefficients, signature (2,-1).
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FORMULA
| a(n) = 2*a(n-1)-a(n-2). - Vincenzo Librandi, Jan 28 2012
G.f.: x*(40*x+7960)/(x-1)^2. - Vincenzo Librandi, Jan 28 2012
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MATHEMATICA
| LinearRecurrence[{2, -1}, {7960, 15960}, 40] (* Vincenzo Librandi, Jan 28 2012 *)
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PROG
| (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
(PARI) for(n=1, 40, print1(8000*n-40", ")); \\ Vincenzo Librandi, Jan 28 2012
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CROSSREFS
| Cf. A157659, A157661.
Sequence in context: A162010 A023322 A064246 * A175507 A126893 A043614
Adjacent sequences: A157657 A157658 A157659 * A157661 A157662 A157663
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KEYWORD
| nonn,easy
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AUTHOR
| Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Mar 04 2009
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