Number of increasing sequences of star chain type with maximal element n.

Terms

a(0) =1a(1) =1a(2) =1a(3) =2a(4) =3a(5) =6a(6) =10a(7) =20a(8) =36a(9) =70a(10) =130a(11) =252a(12) =475a(13) =916a(14) =1745a(15) =3362a(16) =6438a(17) =12410a(18) =23852a(19) =46020a(20) =88697a(21) =171339a(22) =330938a(23) =640189a(24) =1238751a(25) =2399677a(26) =4650819a(27) =9021862a(28) =17510819a(29) =34013311