Number of permutations of 3 copies of 1..n with no element e[i>=2]<e[1+floor((i-2)/6)] (6-way heap).

A178021

Number of permutations of 3 copies of 1..n with no element e[i>=2]<e[1+floor((i-2)/6)] (6-way heap).

Terms

    a(0) =1a(1) =10a(2) =250a(3) =22500a(4) =2788800a(5) =1002405600a(6) =359463283200

External references