a(n) = A216960(n)/2.

Terms

a(0) =0a(1) =0a(2) =0a(3) =0a(4) =1a(5) =0a(6) =2a(7) =1a(8) =3a(9) =3a(10) =6a(11) =5a(12) =13a(13) =12a(14) =28a(15) =25a(16) =58a(17) =53a(18) =118a(19) =115a(20) =243a(21) =236a(22) =505a(23) =480a(24) =1027a(25) =1002a(26) =2068a(27) =2043a(28) =4217a(29) =4127