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90, 333, 738, 1305, 2034, 2925, 3978, 5193, 6570, 8109, 9810, 11673, 13698, 15885, 18234, 20745, 23418, 26253, 29250, 32409, 35730, 39213, 42858, 46665, 50634, 54765, 59058, 63513, 68130, 72909, 77850, 82953, 88218, 93645, 99234, 104985
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| The identity (18n^2+1)^2-(81n^2+9)*(2n)^2=1 can be written as A157889(n)^2-a(n)*A005843(n+1)^2=1. - Vincenzo Librandi, Feb 05 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 (3,-3,1).
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FORMULA
| G.f: x*(90+63*x+9*x^2)/(1-x)^3. - Vincenzo Librandi, Feb 05 2012
a(n) = 3*a(n-1) -3*a(n-2) +a(n-3). - Vincenzo Librandi, Feb 05 2012
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MATHEMATICA
| LinearRecurrence[{3, -3, 1}, {90, 333, 738}, 40] (* Vincenzo Librandi, Feb 05 2012 *)
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PROG
| (MAGMA) I:=[90, 333, 738]; [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 05 2012
(PARI) for(n=1, 40, print1(81*n^2 + 9", ")); \\ Vincenzo Librandi, Feb 05 2012
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CROSSREFS
| Cf. A005843, A157889.
Sequence in context: A044803 A074213 A027621 * A201103 A179962 A158490
Adjacent sequences: A157885 A157886 A157887 * A157889 A157890 A157891
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KEYWORD
| nonn,easy,changed
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AUTHOR
| Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Mar 08 2009
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