A382771 Number of ways to permute the prime indices of n so that the run-lengths are all different.
1, 1, 1, 1, 1, 0, 1, 1, 1, 0, 1, 2, 1, 0, 0, 1, 1, 2, 1, 2, 0, 0, 1, 2, 1, 0, 1, 2, 1, 0, 1, 1, 0, 0, 0, 0, 1, 0, 0, 2, 1, 0, 1, 2, 2, 0, 1, 2, 1, 2, 0, 2, 1, 2, 0, 2, 0, 0, 1, 0, 1, 0, 2, 1, 0, 0, 1, 2, 0, 0, 1, 2, 1, 0, 2, 2, 0, 0, 1, 2, 1, 0, 1, 0, 0, 0, 0
Offset: 1
Keywords
Examples
The a(96) = 4 permutations are: (1,1,1,1,1,2) (1,1,1,2,1,1) (1,1,2,1,1,1) (2,1,1,1,1,1) The a(216) = 4 permutations are: (1,1,2,2,2,1) (1,2,2,2,1,1) (2,1,1,1,2,2) (2,2,1,1,1,2) The a(360) = 6 permutations are: (1,1,1,2,2,3) (1,1,1,3,2,2) (2,2,1,1,1,3) (2,2,3,1,1,1) (3,1,1,1,2,2) (3,2,2,1,1,1)
Crossrefs
Programs
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Mathematica
Table[Length[Select[Permutations[Join@@ConstantArray@@@FactorInteger[n]],UnsameQ@@Length/@Split[#]&]],{n,30}]
Comments