Merging prime factors of n-th composite number.

Terms

a(0) =22a(1) =23a(2) =222a(3) =33a(4) =25a(5) =223a(6) =27a(7) =35a(8) =2222a(9) =233a(10) =225a(11) =37a(12) =211a(13) =2223a(14) =55a(15) =213a(16) =333a(17) =227a(18) =235a(19) =22222a(20) =311a(21) =217a(22) =57a(23) =2233a(24) =219a(25) =313a(26) =2225a(27) =237a(28) =2211a(29) =335