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8040, 16040, 24040, 32040, 40040, 48040, 56040, 64040, 72040, 80040, 88040, 96040, 104040, 112040, 120040, 128040, 136040, 144040, 152040, 160040, 168040, 176040, 184040, 192040, 200040, 208040, 216040, 224040, 232040, 240040, 248040, 256040
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| The identity (80000n^2+800n+1)^2-(100n^2+n)*(8000n+40)^2=1 can be written as A157664(n)^2-A055438(n)*a(n)^2=1 (see the Berselli's comment in A157664). - Vincenzo Librandi, Feb 04 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
| G.f.: x*(8040-40*x)/(1-x)^2. - Vincenzo Librandi, Feb 04 2012
a(n) = 2*a(n-1)-a(n-2). - Vincenzo Librandi, Feb 04 2012
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MATHEMATICA
| LinearRecurrence[{2, -1}, {8040, 16040}, 50] (* Vincenzo Librandi, Feb 04 2012 *)
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PROG
| (MAGMA) I:=[8040, 16040]; [n le 2 select I[n] else 2*Self(n-1)-Self(n-2): n in [1..50]]; // Vincenzo Librandi, Feb 04 2012
(PARI) for(n=1, 50, print1(8000*n + 40", ")); \\ Vincenzo Librandi, Feb 04 2012
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CROSSREFS
| Cf. A055438, A157664.
Sequence in context: A013896 A140929 A184371 * A109486 A032780 A159224
Adjacent sequences: A157660 A157661 A157662 * A157664 A157665 A157666
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KEYWORD
| nonn,easy,changed
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AUTHOR
| Vincenzo Librandi (vincenzo.librandi(AT)tinit), Mar 04 2009
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