a(n)=Product{k=0..n, A003665(k)}.A186270a(n)=Product{k=0..n, A003665(k)}.Terms a(0) =1a(1) =1a(2) =10a(3) =280a(4) =38080a(5) =18887680a(6) =39286374400External referencesoeis: A186270