OFFSET
2,1
LINKS
G. C. Greubel, Table of n, a(n) for n = 2..1000
Index entries for linear recurrences with constant coefficients, signature (4,-6,4,-1).
FORMULA
a(n) = (2*n^3 - 15*n^2 + 19*n - 6)/3!.
G.f.: (z^2 + 3*z - 2)/(z-1)^4.
a(n) = 4*a(n-1) - 6*a(n-2) + 4*a(n-3) - a(n-4).
a(n) - 3*a(n-1) + 3*a(n-2) - a(n-3) = 2*1.
MATHEMATICA
Table[(1/6)*(2*n^3 - 15*n^2 + 19*n - 6), {n, 2, 100}] (* or *) LinearRecurrence[{4, -6, 4, -1}, {-2, -5, -7, -6}, 100] (* G. C. Greubel, Jun 15 2016 *)
CROSSREFS
KEYWORD
easy,sign
AUTHOR
Johannes W. Meijer, Nov 10 2009
STATUS
approved