a(n) = round( (sqrt n)^(sqrt n) ).

Terms

a(0) =1a(1) =2a(2) =3a(3) =4a(4) =6a(5) =9a(6) =13a(7) =19a(8) =27a(9) =38a(10) =53a(11) =74a(12) =102a(13) =139a(14) =189a(15) =256a(16) =344a(17) =460a(18) =612a(19) =811a(20) =1070a(21) =1407a(22) =1842a(23) =2403a(24) =3125a(25) =4050a(26) =5233a(27) =6742a(28) =8662a(29) =11098