OFFSET
0,5
EXAMPLE
The a(1) = 1 through a(8) = 13 compositions:
(1) (11) (111) (13) (113) (1113) (133) (1133)
(31) (131) (1131) (313) (1313)
(1111) (311) (1311) (331) (1331)
(11111) (3111) (11113) (3113)
(111111) (11131) (3131)
(11311) (3311)
(13111) (111113)
(31111) (111131)
(1111111) (111311)
(113111)
(131111)
(311111)
(11111111)
The a(9) = 24 compositions:
(135) (11133) (1111113) (111111111)
(153) (11313) (1111131)
(315) (11331) (1111311)
(351) (13113) (1113111)
(513) (13131) (1131111)
(531) (13311) (1311111)
(31113) (3111111)
(31131)
(31311)
(33111)
MATHEMATICA
normQ[m_]:=Or[m=={}, Union[m]==Range[Max[m]]];
Table[Length[Select[Join@@Permutations/@IntegerPartitions[n], normQ[(#+1)/2]&]], {n, 0, 15}]
CROSSREFS
KEYWORD
nonn
AUTHOR
Gus Wiseman, Aug 30 2022
EXTENSIONS
More terms from Alois P. Heinz, Sep 01 2022
STATUS
approved