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A361645
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a(n) is the least k such that n appears in the k-th row of triangle A361644.
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4
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0, 1, 2, 2, 4, 5, 5, 4, 8, 9, 10, 10, 10, 10, 9, 8, 16, 17, 18, 18, 20, 21, 21, 20, 20, 21, 21, 20, 18, 18, 17, 16, 32, 33, 34, 34, 36, 37, 37, 36, 40, 41, 42, 42, 42, 42, 41, 40, 40, 41, 42, 42, 42, 42, 41, 40, 36, 37, 37, 36, 34, 34, 33, 32, 64, 65, 66, 66
(list;
graph;
refs;
listen;
history;
text;
internal format)
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OFFSET
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0,3
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COMMENTS
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All terms are fibbinary numbers (A003714).
To compute a(n): consider the run lengths in the binary expansion of n (i.e. the n-th row of A101211) and replace from left to right each value v > 1 at odd index with (1, v-1); at the end, there remain the run lengths in the binary expansion of a(n).
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LINKS
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FORMULA
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a(n) <= n with equality iff n is a fibbinary number (A003714).
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EXAMPLE
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The first terms, in decimal and in binary, are:
n a(n) bin(n) bin(a(n))
-- ---- ------ ---------
0 0 0 0
1 1 1 1
2 2 10 10
3 2 11 10
4 4 100 100
5 5 101 101
6 5 110 101
7 4 111 100
8 8 1000 1000
9 9 1001 1001
10 10 1010 1010
11 10 1011 1010
12 10 1100 1010
13 10 1101 1010
14 9 1110 1001
15 8 1111 1000
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PROG
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(PARI) See Links section.
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CROSSREFS
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KEYWORD
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nonn,base
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AUTHOR
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STATUS
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approved
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