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

Terms

a(0) =0a(1) =0a(2) =0a(3) =0a(4) =0a(5) =0a(6) =0a(7) =0a(8) =1a(9) =1a(10) =1a(11) =2a(12) =3a(13) =4a(14) =7a(15) =9a(16) =12a(17) =17a(18) =23a(19) =30a(20) =40a(21) =51a(22) =66a(23) =85a(24) =108a(25) =136a(26) =173a(27) =215a(28) =268a(29) =331