OFFSET
0,2
COMMENTS
Row sums of triangle A132307.
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..1000
Index entries for linear recurrences with constant coefficients, signature (5,-7,3).
FORMULA
Binomial transform of A077552.
a(n) = 2*3^n - n - 1. - Rolf Pleisch, Sep 26 2010
G.f.: (1-x+2*x^2)/((1-3*x)*(1-x)^2). - Bruno Berselli, Mar 31 2011
EXAMPLE
MAPLE
MATHEMATICA
s=1; lst={s}; Do[s+=(n+=s++)+n; AppendTo[lst, s], {n, 0, 5!, 1}]; lst (* Vladimir Joseph Stephan Orlovsky, Nov 15 2008 *)
Table[2*3^n-n-1, {n, 0, 30}] (* or *) LinearRecurrence[{5, -7, 3}, {1, 4, 15}, 30] (* Harvey P. Dale, Aug 06 2013 *)
CoefficientList[Series[(1 - x + 2 x^2)/((1 - 3 x) (1 - x)^2), {x, 0, 50}], x] (* Vincenzo Librandi, Mar 27 2014 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Gary W. Adamson, Aug 18 2007
EXTENSIONS
More terms from Vladimir Joseph Stephan Orlovsky, Nov 15 2008
Wrong formula 2*n^3-n-1 removed by Rolf Pleisch, Oct 19 2010
Simpler definition from Wesley Ivan Hurt, Mar 26 2014
STATUS
approved