a(n) is the least k such that k and k+n are adjacent powerful numbers.

Terms

a(0) =8a(1) =25a(2) =1a(3) =4a(4) =27a(5) =214369a(6) =9a(7) =64a(8) =16a(9) =2187a(10) =3125a(11) =500a(12) =36a(13) =30459361a(14) =49a(15) =128a(16) =512a(17) =225a(18) =81a(19) =21296a(20) =1331a(21) =100467a(22) =625a(23) =1000a(24) =144a(25) =11881a(26) =169a(27) =972a(28) =36963a(29) =6859