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80, 272, 592, 1040, 1616, 2320, 3152, 4112, 5200, 6416, 7760, 9232, 10832, 12560, 14416, 16400, 18512, 20752, 23120, 25616, 28240, 30992, 33872, 36880, 40016, 43280, 46672, 50192, 53840, 57616, 61520, 65552, 69712, 74000, 78416, 82960
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| The identity (8*n^2+1)^2-(64*n^2+16)*n^2 = 1 can be written as A081585(n)^2-a(n)*n^2 = 1. - Vincenzo Librandi, Feb 09 2012
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LINKS
| Vincenzo Librandi, Table of n, a(n) for n = 0..10000
Vincenzo Librandi, X^2-AY^2=1
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FORMULA
| G.f: x*(80+32*x+16*x^2)/(1-x)^3. - Vincenzo Librandi, Feb 09 2012
a(n)=3*a(n-1)-3*a(n-2)+a(n-3). - Vincenzo Librandi, Feb 09 2012
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MATHEMATICA
| 64Range[50]^2+16 (* From Harvey P. Dale, Mar 24 2011 *)
LinearRecurrence[{3, -3, 1}, {80, 272, 592}, 40] (* Vincenzo Librandi, Feb 09 2012 *)
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PROG
| (MAGMA) I:=[80, 272, 592]; [n le 3 select I[n] else 3*Self(n-1)-3*Self(n-2)+Self(n-3): n in [1..50]]; // Vincenzo Librandi, Feb 09 2012
(PARI) for(n=1, 40, print1(64*n^2 + 16", ")); \\ Vincenzo Librandi, Feb 09 2012
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CROSSREFS
| Cf. A081585.
Sequence in context: A202439 A203355 A203348 * A194646 A057441 A204483
Adjacent sequences: A157909 A157910 A157911 * A157913 A157914 A157915
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KEYWORD
| nonn,easy,changed
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AUTHOR
| Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Mar 09 2009
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