OFFSET
3,1
LINKS
G. C. Greubel, Table of n, a(n) for n = 3..1002
Index entries for linear recurrences with constant coefficients, signature (6, -15, 20, -15, 6, -1).
FORMULA
a(n) = (14*n^5 - 115*n^4 + 400*n^3 - 665*n^2 + 486*n - 120)/5!.
G.f.: (z^3 + 9*z^2 + 2*z + 2)/(z-1)^6.
a(n) = 6*a(n-1) - 15*a(n-2) + 20*a(n-3) - 15*a(n-4) + 6*a(n-5) - a(n-6).
a(n) - 5*a(n-1) + 10*a(n-2) - 10*a(n-3) + 5*a(n-4) - a(n-5) = 2*7.
MATHEMATICA
LinearRecurrence[{6, -15, 20, -15, 6, -1}, {2, 14, 63, 209, 559, 1281}, 40] (* or *) Table[1/120*(66*n+95*n^2+40*n^3+25*n^4+14*n^5), {n, 40}] (* Harvey P. Dale, Mar 26 2012 *)
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Johannes W. Meijer, Nov 10 2009
STATUS
approved