Numerator of a remarkable product.

Terms

a(0) =1a(1) =2a(2) =3a(3) =4a(4) =5a(5) =6a(6) =8a(7) =16a(8) =60a(9) =440a(10) =6028a(11) =144672a(12) =5726600a(13) =355049200a(14) =33019575600