Narayana's cows sequence: a(0) = a(1) = a(2) = 1; thereafter a(n) = a(n-1) + a(n-3).

Terms

a(0) =1a(1) =1a(2) =1a(3) =2a(4) =3a(5) =4a(6) =6a(7) =9a(8) =13a(9) =19a(10) =28a(11) =41a(12) =60a(13) =88a(14) =129a(15) =189a(16) =277a(17) =406a(18) =595a(19) =872a(20) =1278a(21) =1873a(22) =2745a(23) =4023a(24) =5896a(25) =8641a(26) =12664a(27) =18560a(28) =27201a(29) =39865