Let n! = 2^a*3^b*5^c*7^d.... in canonical form, then a(n) = concatenation a,b,c,d,...

Terms

a(0) =0a(1) =1a(2) =11a(3) =31a(4) =311a(5) =421a(6) =4211a(7) =7211a(8) =7411a(9) =8421a(10) =84211a(11) =105211a(12) =1052111a(13) =1152211a(14) =1163211a(15) =1563211a(16) =15632111a(17) =16832111a(18) =168321111a(19) =188421111a(20) =189431111a(21) =199432111a(22) =1994321111a(23) =2304321111a(24) =2306321111a(25) =2406322111a(26) =2436322111