a(n) = round(n^(n/2)).

Terms

a(0) =1a(1) =2a(2) =5a(3) =16a(4) =56a(5) =216a(6) =907a(7) =4096a(8) =19683a(9) =100000a(10) =534146a(11) =2985984a(12) =17403307a(13) =105413504a(14) =661735514a(15) =4294967296a(16) =28761784748a(17) =198359290368