a(n) = a(n-1) + a(n-2) - a(n-3) + a(n-4) for n > 4, where a(n)=0 for n < 4 and a(4) = 1.

Terms

a(0) =0a(1) =0a(2) =0a(3) =0a(4) =1a(5) =1a(6) =2a(7) =2a(8) =4a(9) =6a(10) =11a(11) =17a(12) =28a(13) =44a(14) =72a(15) =116a(16) =189a(17) =305a(18) =494a(19) =798a(20) =1292a(21) =2090a(22) =3383a(23) =5473a(24) =8856a(25) =14328a(26) =23184a(27) =37512a(28) =60697a(29) =98209