a(n) = largest prime <= the smallest positive integer with exactly n divisors.

Terms

a(0) =2a(1) =3a(2) =5a(3) =13a(4) =11a(5) =61a(6) =23a(7) =31a(8) =47a(9) =1021a(10) =59a(11) =4093a(12) =191a(13) =139a(14) =113a(15) =65521a(16) =179a(17) =262139a(18) =239a(19) =571a(20) =3067a(21) =4194301a(22) =359a(23) =1291a(24) =12281a(25) =887a(26) =953a(27) =268435399a(28) =719a(29) =1073741789