Number of permutations of 4 copies of 1..n with no element e[i>=2]<e[1+floor((i-2)/3)] (3-way heap).

A178023

Number of permutations of 4 copies of 1..n with no element e[i>=2]<e[1+floor((i-2)/3)] (3-way heap).

Terms

    a(0) =1a(1) =12a(2) =807a(3) =167502a(4) =73291308a(5) =74380051365

External references