%I #5 Oct 04 2012 12:07:16

%S 1,4,20,2000,324000000,16796264976000000000000

%N a(n) = (product of previous terms) * (sum of previous terms), with a(1)=1, a(2)=4.

%e a(3) = (1+4) * (1*4) = 5*4 = 20

%K nonn

%O 1,2

%A _Jon Perry_, Oct 01 2012