Number of permutations of 4 copies of 1..n with no element e[i>=2]<e[1+floor((i-2)/5)] (5-way heap).

A178025

Number of permutations of 4 copies of 1..n with no element e[i>=2]<e[1+floor((i-2)/5)] (5-way heap).

Terms

    a(0) =1a(1) =19a(2) =2265a(3) =1130500a(4) =1023558900

External references