Smallest powerful m in row n of A064364, or -1 if none exist.

Terms

a(0) =1a(1) =-1a(2) =-1a(3) =4a(4) =-1a(5) =8a(6) =-1a(7) =16a(8) =27a(9) =25a(10) =-1a(11) =64a(12) =108a(13) =49a(14) =125a(15) =200a(16) =432a(17) =196a(18) =500a(19) =392a(20) =343a(21) =121a(22) =1323a(23) =1225a(24) =1372a(25) =169a(26) =2744a(27) =968a(28) =5488a(29) =676