Number of permutations of 4 copies of 1..n introduced in order 1..n with no element equal to another within a distance of 3.

A190832

Number of permutations of 4 copies of 1..n introduced in order 1..n with no element equal to another within a distance of 3.

Terms

    a(0) =0a(1) =0a(2) =0a(3) =1a(4) =9993a(5) =44288275a(6) =216956034178

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