OFFSET
1,2
COMMENTS
Every sequence can be uniquely split into a sequence of non-overlapping runs. For example, the runs of (2,2,1,1,1,3,2,2) are ((2,2),(1,1,1),(3),(2,2)), with sums (4,3,3,4). The run-sum trajectory is obtained by repeatedly taking the run-sum transformation (A353847) until the rank of an anti-run is reached. For example, the trajectory 11 -> 10 -> 8 corresponds to the trajectory (2,1,1) -> (2,2) -> (4).
The k-th composition in standard order (graded reverse-lexicographic, A066099) is obtained by taking the set of positions of 1's in the reversed binary expansion of k, prepending 0, taking first differences, and reversing again. This gives a bijective correspondence between nonnegative integers and integer compositions.
EXAMPLE
The terms together with their binary expansions and corresponding compositions begin:
1: 1 (1)
2: 10 (2)
3: 11 (1,1)
4: 100 (3)
7: 111 (1,1,1)
8: 1000 (4)
10: 1010 (2,2)
11: 1011 (2,1,1)
14: 1110 (1,1,2)
15: 1111 (1,1,1,1)
16: 10000 (5)
31: 11111 (1,1,1,1,1)
32: 100000 (6)
36: 100100 (3,3)
39: 100111 (3,1,1,1)
42: 101010 (2,2,2)
46: 101110 (2,1,1,2)
59: 111011 (1,1,2,1,1)
60: 111100 (1,1,1,3)
63: 111111 (1,1,1,1,1,1)
MATHEMATICA
stc[n_]:=Differences[Prepend[Join@@ Position[Reverse[IntegerDigits[n, 2]], 1], 0]]//Reverse;
Select[Range[100], Length[FixedPoint[Total/@Split[#]&, stc[#]]]==1&]
CROSSREFS
The version for partitions is A353844.
These compositions are counted by A353858.
A005811 counts runs in binary expansion.
A011782 counts compositions.
A066099 lists compositions in standard order.
A318928 gives runs-resistance of binary expansion.
A333627 ranks the run-lengths of standard compositions.
A353932 lists run-sums of standard compositions.
KEYWORD
nonn
AUTHOR
Gus Wiseman, Jun 01 2022
STATUS
approved