Denominator of Sum/Product of first n numbers.

Terms

a(0) =1a(1) =2a(2) =1a(3) =12a(4) =8a(5) =240a(6) =180a(7) =1120a(8) =8064a(9) =725760a(10) =604800a(11) =79833600a(12) =68428800a(13) =830269440a(14) =10897286400