Number of Carlitz compositions of n with exactly two descents.

Terms

a(0) =2a(1) =5a(2) =12a(3) =27a(4) =53a(5) =98a(6) =174a(7) =296a(8) =486a(9) =781a(10) =1222a(11) =1874a(12) =2827a(13) =4195a(14) =6138a(15) =8873a(16) =12675a(17) =17918a(18) =25095a(19) =34832a(20) =47954a(21) =65529a(22) =88911a(23) =119842a(24) =160552a(25) =213841a(26) =283266a(27) =373318a(28) =489601a(29) =639149