a(n) is obtained by applying the map k -> composite(k) n times, starting at n.

Terms

a(0) =4a(1) =12a(2) =25a(3) =39a(4) =60a(5) =94a(6) =133a(7) =183a(8) =236a(9) =320a(10) =415a(11) =520a(12) =640a(13) =805a(14) =1007a(15) =1212a(16) =1463a(17) =1800a(18) =2144a(19) =2562a(20) =3021a(21) =3523a(22) =4135a(23) =4840a(24) =5747a(25) =6630a(26) =7701a(27) =9057a(28) =10392a(29) =11812