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A154262
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9n^2 - 10n + 3.
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4
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3, 2, 19, 54, 107, 178, 267, 374, 499, 642, 803, 982, 1179, 1394, 1627, 1878, 2147, 2434, 2739, 3062, 3403, 3762, 4139, 4534, 4947, 5378, 5827, 6294, 6779, 7282, 7803, 8342, 8899, 9474, 10067, 10678, 11307, 11954, 12619, 13302, 14003, 14722, 15459
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,1
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COMMENTS
| The identity (81n^2+72n+17)^2-(9n^2+8n+2)*(27n+12)^2=1 can be written as A154295(n+1)^2-a(n+1)*A154266(n)^2=1. - Vincenzo Librandi, Feb 03 2012
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LINKS
| Vincenzo Librandi, Table of n, a(n) for n = 0..10000
Index entries for sequences related to linear recurrences with constant coefficients, signature (3,-3,1).
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FORMULA
| G.f.: (3-7*x+22*x^2)/(1-x)^3. - Vincenzo Librandi, Feb 02 2012
a(n) = 3*a(n-1)-3*a(n-2)+a(n-3). - Vincenzo Librandi, Feb 02 2012
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MATHEMATICA
| LinearRecurrence[{3, -3, 1}, {2, 19, 54}, 50] (* Vincenzo Librandi, Feb 02 2012 *)
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PROG
| (PARI) a(n)=9*n^2-10*n+3 \\ Charles R Greathouse IV, Dec 27 2011
(MAGMA) I:=[2, 19, 54]; [n le 3 select I[n] else 3*Self(n-1)-3*Self(n-2)+1*Self(n-3): n in [1..40]]; // Vincenzo Librandi, Feb 02 2012
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CROSSREFS
| Cf. A154266, A154295.
Sequence in context: A066195 A090587 A094554 * A154261 A098655 A065038
Adjacent sequences: A154259 A154260 A154261 * A154263 A154264 A154265
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KEYWORD
| nonn,easy,changed
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AUTHOR
| Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Jan 06 2009
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EXTENSIONS
| Edited by Charles R Greathouse IV (charles.greathouse(AT)case.edu), Jul 25 2010
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