a(0)=a(1)=a(2)=a(3)=a(4)=a(5)=1; a(n)=a(n-1)+a(n-2)-a(n-4)+a(n-6) for n>=6.

Terms

a(0) =1a(1) =1a(2) =1a(3) =1a(4) =1a(5) =1a(6) =2a(7) =3a(8) =5a(9) =8a(10) =12a(11) =18a(12) =27a(13) =40a(14) =60a(15) =90a(16) =135a(17) =203a(18) =305a(19) =458a(20) =688a(21) =1033a(22) =1551a(23) =2329a(24) =3497a(25) =5251a(26) =7885a(27) =11840a(28) =17779a(29) =26697