Largest power of n not exceeding 2^n.

Terms

a(0) =4a(1) =3a(2) =16a(3) =25a(4) =36a(5) =49a(6) =64a(7) =81a(8) =1000a(9) =1331a(10) =1728a(11) =2197a(12) =2744a(13) =3375a(14) =65536a(15) =83521a(16) =104976a(17) =130321a(18) =160000a(19) =194481a(20) =234256a(21) =6436343a(22) =7962624a(23) =9765625a(24) =11881376a(25) =14348907a(26) =17210368a(27) =20511149a(28) =729000000a(29) =887503681