a(n) = a(n-1) + 2*a(n-2) - 2*a(n-3) + a(n-5).

Terms

a(0) =1a(1) =1a(2) =3a(3) =3a(4) =7a(5) =8a(6) =17a(7) =22a(8) =43a(9) =60a(10) =110a(11) =161a(12) =283a(13) =428a(14) =732a(15) =1132a(16) =1901a(17) =2984a(18) =4950a(19) =7848a(20) =12912a(21) =20609a(22) =33721a(23) =54065a(24) =88137a(25) =141737a(26) =230490a(27) =371411a(28) =602982a(29) =972961