Shifts 3 places left under binomial transform.

Terms

a(0) =1a(1) =0a(2) =0a(3) =1a(4) =1a(5) =1a(6) =2a(7) =6a(8) =17a(9) =44a(10) =112a(11) =304a(12) =918a(13) =3040a(14) =10623a(15) =38161a(16) =140074a(17) =528594a(18) =2068751a(19) =8436893a(20) =35813251a(21) =157448068a(22) =713084042a(23) =3315414747a(24) =15805117878a(25) =77273097114a(26) =387692392570