Denominators of the sum of the reciprocals of the Collatz (3x+1) sequence beginning at n.

Terms

a(0) =1a(1) =2a(2) =240a(3) =4a(4) =80a(5) =80a(6) =272272a(7) =8a(8) =350064a(9) =80a(10) =38896a(11) =240a(12) =208a(13) =272272a(14) =4095840a(15) =16a(16) =3536a(17) =116688a(18) =21431696a(19) =80a(20) =1344a(21) =38896a(22) =1365280a(23) =80a(24) =535792400a(25) =208a(27) =38896a(28) =1127984a(29) =1365280