OFFSET
0,2
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..1000
Index entries for linear recurrences with constant coefficients, signature (4,-5,2). [From R. J. Mathar, May 21 2010]
FORMULA
Binomial transform of [1, 3, 2, 0, 2, 0, 2, 0, 2, ...].
From R. J. Mathar, May 21 2010: (Start)
G.f.:= (2*x^2 + 2*x^3 - 1)/((2*x-1)*(x-1)^2).
a(n) = 2^n + 3*n - 1, n > 0. (End)
a(n) = 4*a(n-1) - 5*a(n-2) + 2*a(n-3). - Vincenzo Librandi, Jul 06 2012
EXAMPLE
a(4) = 27 = sum of row 4 terms of triangle A132073: (5 + 5 + 7 + 5 + 5).
a(4) = 27 = (1, 4, 6, 4, 1) dot (1, 3, 2, 0, 2) = (1 + 12 + 12 + 0 + 2).
MATHEMATICA
CoefficientList[Series[(2*x^2+2*x^3-1)/((2*x-1)*(x-1)^2), {x, 0, 40}], x] (* Vincenzo Librandi, Jul 06 2012 *)
PROG
(Magma) I:=[1, 4, 9, 16]; [n le 4 select I[n] else 4*Self(n-1)-5*Self(n-2)+2*Self(n-3): n in [1..40]]; // Vincenzo Librandi, Jul 06 2012
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Gary W. Adamson, Aug 09 2007
EXTENSIONS
More terms from R. J. Mathar, May 21 2010
STATUS
approved