Cubefree part of n!!.

Terms

a(0) =1a(1) =2a(2) =3a(3) =1a(4) =15a(5) =6a(6) =105a(7) =6a(8) =35a(9) =60a(10) =385a(11) =90a(12) =5005a(13) =1260a(14) =75075a(15) =315a(16) =1276275a(17) =210a(18) =24249225a(19) =525a(20) =509233725a(21) =11550a(22) =11712375675a(23) =34650a(24) =2342475135a(25) =900900a(26) =2342475135a(27) =3153150a(28) =67931778915a(29) =28028