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

A178022

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

Terms

    a(0) =1a(1) =7a(2) =206a(3) =18155a(4) =3340366a(5) =1345907216a(6) =965180428296

External references