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

A334647

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

Terms

    a(0) =0a(1) =5a(2) =16a(3) =78a(4) =470a(5) =3153a(6) =22588a(7) =169188a(8) =1308762a(9) =10374460a(10) =83829856a(11) =687929086a(12) =5717602930a(13) =48030047206a(14) =407142435000

External references