OFFSET
0,1
LINKS
Robert Israel, Table of n, a(n) for n = 0..830
FORMULA
a(n) = C(2+2*n, n) * C(7+2*n, 2+n).
From Robert Israel, Dec 16 2018: (Start)
24*(11+2*n)*(5+2*n)*(n+3)*a(n+1)-2*(n+4)*(11*n^2+112*n+252)*a(n+2)+(8+n)*(n+5)*(n+3)*a(n+3)=0. (End)
EXAMPLE
if n=0 then C(2+2*0,0)*C(7+2*0,2+0)=C(2,0)*C(7,2)=1*21=21;
if n=7 then C(2+2*7,7)*C(7+2*7,2+7)=C(16,7)*C(21,9)=11440*293930=3362559200;
if n=10 then C(2+2*10,10)*C(7+2*10,2+10)=C(22,10)*C(27,12)=646646*17383860=11241203533560.
MAPLE
seq(binomial(2+2*n, n)*binomial(7+2*n, 2+n), n=0..20); # Robert Israel, Dec 16 2018
MATHEMATICA
nmax = 10; NN[5, m_, x_] := x^m*(2*m+5)!*Hypergeometric2F1[-m, -m, -2*m-5, (x-1)/x]/((m+5)!*m!); tri = Table[CoefficientList[NN[5, m, x], x], {m, 0, 2*nmax+2}]; Table[tri[[2n+3, n+3]], {n, 0, nmax}] (* Jean-François Alcover, Sep 18 2013 *)
PROG
(PARI) a(n) = binomial(2+2*n, n)*binomial(7+2*n, 2+n); \\ Michel Marcus, Sep 18 2013
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Zerinvary Lajos, Jan 28 2006
EXTENSIONS
Simpler name and more terms added by Joerg Arndt, Sep 18 2013
STATUS
approved