Number of compositions of n with exactly seven descents.

Terms

a(0) =21a(1) =259a(2) =1932a(3) =10898a(4) =51083a(5) =208936a(6) =768594a(7) =2594957a(8) =8158005a(9) =24140097a(10) =67794864a(11) =181889780a(12) =468678716a(13) =1164905882a(14) =2803070038a(15) =6549961919a(16) =14901997455a(17) =33085162997a(18) =71822232573a(19) =152710556875a(20) =318509850193a(21) =652536555773