A332296 Number of narrowly totally normal compositions of n.

1, 1, 2, 4, 5, 7, 13, 23, 30, 63, 120, 209, 369, 651, 1198, 2174, 3896, 7023, 12699, 22941, 41565

Offset: 0

Author

Gus Wiseman, Feb 15 2020

Keywords

• nonn
• more

Comments

A sequence is narrowly totally normal if either it is empty, a singleton (narrow), or it covers an initial interval of positive integers (normal) with narrowly totally normal run-lengths.

A composition of n is a finite sequence of positive integers summing to n.

Examples

			The a(0) = 1 through a(6) = 13 compositions:
  ()  (1)  (2)   (3)    (4)     (5)      (6)
           (11)  (12)   (112)   (122)    (123)
                 (21)   (121)   (212)    (132)
                 (111)  (211)   (221)    (213)
                        (1111)  (1121)   (231)
                                (1211)   (312)
                                (11111)  (321)
                                         (1212)
                                         (1221)
                                         (2112)
                                         (2121)
                                         (11211)
                                         (111111)
For example, starting with the composition (1,1,2,3,1,1) and repeatedly taking run-lengths gives (1,1,2,3,1,1) -> (2,1,1,2) -> (1,2,1) -> (1,1,1) -> (3). The first four are normal and the last is a singleton, so (1,1,2,3,1,1) is counted under a(9).
		

Crossrefs

Normal compositions are A107429.

The wide version is A332279.

The wide recursive version (for partitions) is A332295.

The alternating version is A332296 (this sequence).

The strong version is A332336.

The co-strong version is (also) A332336.

Cf. A001462, A316496, A317081, A317245, A317491, A329744, A332276, A332277, A332278, A332297, A332337, A332340.

Programs

Mathematica

tinQ[q_]:=Or[Length[q]<=1,And[Union[q]==Range[Max[q]],tinQ[Length/@Split[q]]]];
Table[Length[Select[Join@@Permutations/@IntegerPartitions[n],tinQ]],{n,0,10}]

Formula

For n > 1, a(n) = A332279(n) + 1.