Sum of exponents in prime-power factorization of C(3n,n-1).

Terms

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