Number of ballot sequences of length n having exactly four descents.

A241797

Number of ballot sequences of length n having exactly four descents.

Terms

    a(0) =9a(1) =146a(2) =1324a(3) =8786a(4) =47013a(5) =214997a(6) =874413a(7) =3228005a(8) =11049817a(9) =35389760a(10) =107476721a(11) =310853113a(12) =863984856a(13) =2313084483a(14) =6003120701a(15) =15122836712a(16) =37154716734a(17) =89093938147a(18) =209258012995a(19) =481663102867

External references