Partial products of pi(n), A000720.

Terms

a(0) =1a(1) =1a(2) =2a(3) =4a(4) =12a(5) =36a(6) =144a(7) =576a(8) =2304a(9) =9216a(10) =46080a(11) =230400a(12) =1382400a(13) =8294400a(14) =49766400a(15) =298598400a(16) =2090188800a(17) =14631321600a(18) =117050572800a(19) =936404582400