Number of compositions (ordered partitions) of n into 1's, 2's and 4's.

Terms

a(0) =1a(1) =1a(2) =2a(3) =3a(4) =6a(5) =10a(6) =18a(7) =31a(8) =55a(9) =96a(10) =169a(11) =296a(12) =520a(13) =912a(14) =1601a(15) =2809a(16) =4930a(17) =8651a(18) =15182a(19) =26642a(20) =46754a(21) =82047a(22) =143983a(23) =252672a(24) =443409a(25) =778128a(26) =1365520a(27) =2396320a(28) =4205249a(29) =7379697