Powerful numbers whose prime factors are all of the form 3*k + 1.

Terms

a(0) =1a(1) =49a(2) =169a(3) =343a(4) =361a(5) =961a(6) =1369a(7) =1849a(8) =2197a(9) =2401a(10) =3721a(11) =4489a(12) =5329a(13) =6241a(14) =6859a(15) =8281a(16) =9409a(17) =10609a(18) =11881a(19) =16129a(20) =16807a(21) =17689a(22) =19321a(23) =22801a(24) =24649a(25) =26569a(26) =28561a(27) =29791a(28) =32761a(29) =37249