Denominator of the sum of the reciprocals of the first n nonprimes.

Terms

a(0) =1a(1) =4a(2) =12a(3) =24a(4) =72a(5) =360a(6) =360a(7) =2520a(8) =504a(9) =1008a(10) =336a(11) =1680a(12) =1680a(13) =18480a(14) =18480a(15) =92400a(16) =1201200a(17) =10810800a(18) =10810800a(19) =10810800a(20) =21621600a(21) =21621600a(22) =367567200a(23) =52509600a(24) =52509600a(25) =997682400a(26) =997682400a(27) =997682400a(28) =6983776800a(29) =6983776800