Consider three sequences an A.P., a G.P. and a H.P. as follows 
 $a,A_1,A_2,A_3\mathrm{.......}{A}_9,b(A.P.)$
 $a,G_1,G_2,G_3,\mathrm{....}{G}_9,b(G.P.);$
 $a,H_1,H_2,H_3,\mathrm{......}{H}_9,b(H.P.)$
If  $a,b$ are both roots of the equation  $x^2-(p+1)x+16=0,p\in R$ , then the value of  $\prod _{r=1}^4{A}_r{H}_{10-r}{G}_{10-2r}$  is