Powerful numbers whose prime factors are all of the form 4*k + 1.

Terms

a(0) =1a(1) =25a(2) =125a(3) =169a(4) =289a(5) =625a(6) =841a(7) =1369a(8) =1681a(9) =2197a(10) =2809a(11) =3125a(12) =3721a(13) =4225a(14) =4913a(15) =5329a(16) =7225a(17) =7921a(18) =9409a(19) =10201a(20) =11881a(21) =12769a(22) =15625a(23) =18769a(24) =21025a(25) =21125a(26) =22201a(27) =24389a(28) =24649a(29) =28561