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

Terms

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