The OEIS is supported by the many generous donors to the OEIS Foundation.
%I #2 Mar 30 2012 18:59:02
%S 1,3,9,18,54,108,216,648,1944,3888,7776,23328,46656,139968,419904,
%T 839808,2519424,5038848,10077696,30233088,60466176,181398528,
%U 544195584,1088391168,2176782336,6530347008,19591041024,39182082048,117546246144
%N a(n)=Product{k=0..n, 1+2^A010060(k)}/2.
%K easy,nonn
%O 0,2
%A _Paul Barry_, Dec 10 2004