a(n) = a(n-1) + a(n-3) + a(n-4), n >= 4, with initial terms 1,-1,2,3.

Terms

a(0) =1a(1) =-1a(2) =2a(3) =3a(4) =3a(5) =4a(6) =9a(7) =15a(8) =22a(9) =35a(10) =59a(11) =96a(12) =153a(13) =247a(14) =402a(15) =651a(16) =1051a(17) =1700a(18) =2753a(19) =4455a(20) =7206a(21) =11659a(22) =18867a(23) =30528a(24) =49393a(25) =79919a(26) =129314a(27) =209235a(28) =338547a(29) =547780