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

A178019

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

Terms

    a(0) =1a(1) =7a(2) =170a(3) =8870a(4) =976720a(5) =216658080a(6) =99152064000

External references