A354906 revision #5
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A354906
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Position of first appearance of n in A354579 = Number of distinct run-lengths of standard compositions.
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1
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OFFSET
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0,3
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COMMENTS
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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.
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LINKS
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EXAMPLE
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The terms together with their corresponding compositions begin:
0: ()
1: (1)
11: (2,1,1)
119: (1,1,2,1,1,1)
5615: (2,2,1,1,1,2,1,1,1,1)
251871: (1,1,1,2,2,1,1,1,1,2,1,1,1,1,1)
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MATHEMATICA
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stc[n_]:=Differences[Prepend[Join@@Position[Reverse[IntegerDigits[n, 2]], 1], 0]]//Reverse;
pd=Table[Length[Union[Length/@Split[stc[n]]]], {n, 0, 10000}];
Table[Position[pd, n][[1, 1]]-1, {n, 0, Max@@pd}]
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CROSSREFS
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For run-sums instead of run-lengths we have A246534 (firsts in A353849).
These are the positions of first appearances in A354579.
A005811 counts runs in binary expansion.
A333627 ranks the run-lengths of standard compositions.
A351596 ranks compositions with distinct run-lengths, counted by A329739.
A353744 ranks compositions with equal run-lengths, counted by A329738.
A353852 ranks compositions with distinct run-sums, counted by A353850.
A353853-A353859 are sequences pertaining to composition run-sum trajectory.
A353860 counts collapsible compositions.
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KEYWORD
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nonn,more
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AUTHOR
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STATUS
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editing
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