OFFSET
0,1
LINKS
Index entries for linear recurrences with constant coefficients, signature (9,-36,84,-126,126,-84,36,-9,1).
FORMULA
From R. J. Mathar, Nov 29 2015: (Start)
G.f.: ( -126+84*x-36*x^2+9*x^3-x^4 ) / (x-1)^9. (End)
From Amiram Eldar, Aug 30 2022: (Start)
Sum_{n>=0} 1/a(n) = 9/980.
Sum_{n>=0} (-1)^n/a(n) = 1/140. (End)
EXAMPLE
If n=0 then C(0+4,0+0)*C(0+9,4) = C(4,0)*C(9,4) = 1*126 = 126.
If n=5 then C(5+4,5+0)*C(5+9,4) = C(9,5)*C(14,4) = 126*1001 = 126126.
MAPLE
A104678:=n->binomial(n+4, n)*binomial(n+9, 4); seq(A104678(n), n=0..100); # Wesley Ivan Hurt, Dec 03 2013
MATHEMATICA
Table[Binomial[n + 4, n] Binomial[n + 9, 4], {n, 0, 100}] (* Wesley Ivan Hurt, Dec 03 2013 *)
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Zerinvary Lajos, Apr 22 2005
STATUS
approved