a(n) = (10*n + 7)^3.

Terms

a(0) =343a(1) =4913a(2) =19683a(3) =50653a(4) =103823a(5) =185193a(6) =300763a(7) =456533a(8) =658503a(9) =912673a(10) =1225043a(11) =1601613a(12) =2048383a(13) =2571353a(14) =3176523a(15) =3869893a(16) =4657463a(17) =5545233a(18) =6539203a(19) =7645373a(20) =8869743a(21) =10218313a(22) =11697083