Squares in A064491.

Terms

a(0) =1a(1) =4a(2) =9a(3) =64a(4) =81a(5) =784a(6) =1521a(7) =29584a(8) =34225a(9) =132496a(10) =136161a(11) =4999696a(12) =5076009a(13) =15492096a(14) =15547249a(15) =299982400a(16) =300086329a(17) =1849172004a(18) =1849430025