Number of subsets of {2..n} such that the product of the elements is a perfect power.

Terms

a(0) =1a(1) =1a(2) =1a(3) =1a(4) =3a(5) =3a(6) =5a(7) =5a(8) =11a(9) =25a(10) =41a(11) =41a(12) =80a(13) =80a(14) =144a(15) =284a(16) =568a(17) =568a(18) =1147a(19) =1147a(20) =2339a(21) =4667a(22) =8763a(23) =8763a(24) =17548a(25) =35196a(26) =67964a(27) =135918a(28) =273806a(29) =273806