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A157264 a(n) = 10368*n^2 - 15840*n + 6049. 3
577, 15841, 51841, 108577, 186049, 284257, 403201, 542881, 703297, 884449, 1086337, 1308961, 1552321, 1816417, 2101249, 2406817, 2733121, 3080161, 3447937, 3836449, 4245697, 4675681, 5126401, 5597857, 6090049, 6602977 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
The identity (10368*n^2-15840*n+6049)^2-(36*n^2-55*n+21)*(1728*n-1320)^2=1 can be written as a(n)^2-A157262(n)*A157263(n)^2=1. - Vincenzo Librandi, Jan 27 2012
LINKS
Vincenzo Librandi, X^2-AY^2=1
FORMULA
a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3). - Vincenzo Librandi, Jan 27 2012
G.f.: x*(-577-14110*x-6049*x^2)/(x-1)^3. - Vincenzo Librandi, Jan 27 2012
E.g.f.: (10368*x^2 - 5472*x + 6049)*exp(x) - 6049. - G. C. Greubel, Feb 04 2018
MATHEMATICA
LinearRecurrence[{3, -3, 1}, {577, 15841, 51841}, 40] (* Vincenzo Librandi, Jan 27 2012 *)
PROG
(Magma) I:=[577, 15841, 51841]; [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, Jan 27 2012
(PARI) for(n=1, 40, print1(10368*n^2 - 15840*n + 6049", ")); \\ Vincenzo Librandi, Jan 27 2012
CROSSREFS
Sequence in context: A278740 A101249 A202011 * A201046 A154511 A221331
KEYWORD
nonn,easy
AUTHOR
Vincenzo Librandi, Feb 26 2009
STATUS
approved

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Last modified March 1 13:16 EST 2024. Contains 370433 sequences. (Running on oeis4.)