a(n) is the total number of down steps between the third and fourth up steps in all 3_1-Dyck paths of length 4*n.

A334649

a(n) is the total number of down steps between the third and fourth up steps in all 3_1-Dyck paths of length 4*n.

Terms

    a(0) =0a(1) =0a(2) =0a(3) =236a(4) =1034a(5) =6094a(6) =40996a(7) =295740a(8) =2231022a(9) =17370163a(10) =138473536a(11) =1124433142a(12) =9266859394a(13) =77307427741a(14) =651540030688

External references