Number of permutations of 3 copies of 1..n with all adjacent differences <= 4 in absolute value.

A177294

Number of permutations of 3 copies of 1..n with all adjacent differences <= 4 in absolute value.

Terms

    a(0) =1a(1) =1a(2) =20a(3) =1680a(4) =369600a(5) =168168000a(6) =41494252800

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