a(1)=0; thereafter a(2k)=k+a(k), a(2k+1)=k+a(6k+4).

Terms

a(0) =0a(1) =1a(2) =23a(3) =3a(4) =17a(5) =26a(6) =141a(7) =7a(8) =166a(9) =22a(10) =127a(11) =32a(12) =58a(13) =148a(14) =344a(15) =15a(16) =105a(17) =175a(18) =256a(19) =32a(20) =73a(21) =138a(22) =314a(23) =44a(24) =325a(25) =71a(26) =50699a(27) =162a(28) =218a(29) =359