Greatest prime closest to n^3.

Terms

a(0) =2a(1) =7a(2) =29a(3) =67a(4) =127a(5) =211a(6) =347a(7) =509a(8) =727a(9) =997a(10) =1327a(11) =1733a(12) =2203a(13) =2741a(14) =3373a(15) =4099a(16) =4909a(17) =5827a(18) =6857a(19) =7993a(20) =9257a(21) =10651a(22) =12163a(23) =13829a(24) =15629a(25) =17579a(26) =19681a(27) =21961a(28) =24391a(29) =26993