a(n) = n-1 for n <= 2; thereafter a(n) = A238824(n-2) + A238832(n-1).

Terms

a(0) =0a(1) =1a(2) =0a(3) =2a(4) =2a(5) =7a(6) =16a(7) =40a(8) =101a(9) =246a(10) =615a(11) =1504a(12) =3724a(13) =9147a(14) =22567a(15) =55541a(16) =136884a(17) =337128a(18) =830628a(19) =2046145a(20) =5040932a(21) =12418320a(22) =30593281a(23) =75367352a(24) =185670647a(25) =457405836a(26) =1126836394a(27) =2776001211a(28) =6838779857a(29) =16847579205