Number of compositions of n that are not strictly increasing.

Terms

a(0) =0a(1) =0a(2) =1a(3) =2a(4) =6a(5) =13a(6) =28a(7) =59a(8) =122a(9) =248a(10) =502a(11) =1012a(12) =2033a(13) =4078a(14) =8170a(15) =16357a(16) =32736a(17) =65498a(18) =131026a(19) =262090a(20) =524224a(21) =1048500a(22) =2097063a(23) =4194200a(24) =8388486a(25) =16777074a(26) =33554267a(27) =67108672a(28) =134217506a(29) =268435200