Number of compositions of n with exactly four descents.

Terms

a(0) =5a(1) =37a(2) =189a(3) =751a(4) =2558a(5) =7762a(6) =21577a(7) =55867a(8) =136478a(9) =317416a(10) =707817a(11) =1521755a(12) =3168262a(13) =6410970a(14) =12646075a(15) =24378923a(16) =46028497a(17) =85269218a(18) =155238256a(19) =278130152a(20) =490983234a(21) =854910432a(22) =1469679627a(23) =2496560526a(24) =4193815403a(25) =6971437570a(26) =11474937414a(27) =18712755604