Powerful numbers k such that both k-1 and k+1 are in A126706.

Terms

a(0) =49a(1) =125a(2) =243a(3) =343a(4) =1681a(5) =1849a(6) =3249a(7) =4913a(8) =6724a(9) =6859a(10) =8649a(11) =9801a(12) =11449a(13) =13689a(14) =13924a(15) =17576a(16) =20449a(17) =24389a(18) =24649a(19) =28125a(20) =28224a(21) =29791a(22) =31212a(23) =36125a(24) =37249a(25) =40328a(26) =42849a(27) =45125a(28) =57121a(29) =59049