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

A190918

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

Terms

    a(0) =1a(1) =36a(2) =1721a(3) =94376a(4) =5609649a(5) =351574834a(6) =22875971289

External references