Number of ways to choose a distinct subsequence of an integer composition of n.

Terms

a(0) =1a(1) =2a(2) =5a(3) =14a(4) =37a(5) =98a(6) =259a(7) =682a(8) =1791a(9) =4697a(10) =12303a(11) =32196a(12) =84199a(13) =220087a(14) =575067a(15) =1502176a(16) =3923117a(17) =10244069a(18) =26746171a(19) =69825070a(20) =182276806a(21) =475804961a(22) =1241965456a(23) =3241732629a(24) =8461261457a(25) =22084402087a(26) =57640875725a(27) =150442742575a(28) =392652788250