a(n) = A048141(3*n+2).

Terms

a(0) =0a(1) =0a(2) =1a(3) =1a(4) =1a(5) =2a(6) =4a(7) =5a(8) =7a(9) =9a(10) =11a(11) =15a(12) =20a(13) =25a(14) =33a(15) =40a(16) =48a(17) =60a(18) =74a(19) =89a(20) =108a(21) =130a(22) =157a(23) =187a(24) =222a(25) =262a(26) =311a(27) =365a(28) =427a(29) =500