Number of Dyck paths of semilength n having exactly 4 (possibly overlapping) occurrences of the consecutive steps UDUUUDDDUD (with U=(1,1), D=(1,-1)).
A243874
Number of Dyck paths of semilength n having exactly 4 (possibly overlapping) occurrences of the consecutive steps UDUUUDDDUD (with U=(1,1), D=(1,-1)).
Terms
- a(0) =1a(1) =6a(2) =31a(3) =156a(4) =766a(5) =3717a(6) =17812a(7) =84342a(8) =395152a(9) =1833853a(10) =8438976a(11) =38540936a(12) =174819086a(13) =788082431a(14) =3532770025a(15) =15755543925a(16) =69937932805a(17) =309113716505
External references
- oeis: A243874