a(n) is the sum of exponents in the prime factorization of lcm{C(n,0), C(n,1), ..., C(n,n)}.

Terms

a(0) =0a(1) =0a(2) =1a(3) =1a(4) =3a(5) =2a(6) =4a(7) =3a(8) =5a(9) =5a(10) =7a(11) =5a(12) =8a(13) =7a(14) =7a(15) =6a(16) =10a(17) =8a(18) =11a(19) =9a(20) =10a(21) =10a(22) =12a(23) =9a(24) =12a(25) =12a(26) =12a(27) =12a(28) =15a(29) =13