OFFSET
1,4
EXAMPLE
The a(6) = 7 relatively prime Lyndon compositions are 15, 114, 132, 123, 1113, 1122, 11112.
The a(7) = 17 relatively prime Lyndon compositions:
16, 25, 34,
115, 142, 124, 133, 223,
1114, 1213, 1132, 1123, 1222,
11113, 11212, 11122,
111112.
MATHEMATICA
LyndonQ[q_]:=Array[OrderedQ[{q, RotateRight[q, #]}]&, Length[q]-1, 1, And]&&Array[RotateRight[q, #]&, Length[q], 1, UnsameQ];
Table[Length[Select[Join@@Permutations/@IntegerPartitions[n], LyndonQ[#]&&GCD@@#==1&]], {n, 10}]
CROSSREFS
KEYWORD
nonn
AUTHOR
Gus Wiseman, Sep 02 2018
STATUS
approved