A167585 a(n) = 12*n^2 - 8*n + 9.
13, 41, 93, 169, 269, 393, 541, 713, 909, 1129, 1373, 1641, 1933, 2249, 2589, 2953, 3341, 3753, 4189, 4649, 5133, 5641, 6173, 6729, 7309, 7913, 8541, 9193, 9869, 10569, 11293, 12041, 12813, 13609, 14429, 15273, 16141, 17033, 17949, 18889
Offset: 1
Links
- G. C. Greubel, Table of n, a(n) for n = 1..1000
- Index entries for linear recurrences with constant coefficients, signature (3,-3,1).
Programs
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Mathematica
LinearRecurrence[{3, -3, 1}, {13, 41, 93}, 100] (* G. C. Greubel, Jun 17 2016 *) -
PARI
a(n)=12*n^2-8*n+9 \\ Charles R Greathouse IV, Jun 17 2017
Formula
GF(z) = (9*z^2 + 2*z + 13)/(1-z)^3.
a(n) = a(n-1) + 24*n - 20, with a(1)=13. - Vincenzo Librandi, Dec 03 2010
a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3). - G. C. Greubel, Jun 17 2016
Comments