a(n) = A091137(n) / A016116(n).

Terms

a(0) =1a(1) =2a(2) =6a(3) =12a(4) =180a(5) =360a(6) =7560a(7) =15120a(8) =226800a(9) =453600a(10) =14968800a(11) =29937600a(12) =40864824000a(13) =81729648000