a(n) = a(n-1) + a(n-3) + a(n-4), where a(0) = 0, a(1) = 2, a(2) = 0, a(3) = 1.

Terms

a(0) =0a(1) =2a(2) =0a(3) =1a(4) =3a(5) =5a(6) =6a(7) =10a(8) =18a(9) =29a(10) =45a(11) =73a(12) =120a(13) =194a(14) =312a(15) =505a(16) =819a(17) =1325a(18) =2142a(19) =3466a(20) =5610a(21) =9077a(22) =14685a(23) =23761a(24) =38448a(25) =62210a(26) =100656a(27) =162865a(28) =263523a(29) =426389