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A376674
a(n) is the unique number k different from n such that the words A376637(n) and A376637(k) have the same run lengths transform.
2
2, 1, 6, 5, 4, 3, 10, 9, 8, 7, 16, 15, 14, 13, 12, 11, 24, 23, 22, 21, 20, 19, 18, 17, 28, 27, 26, 25, 40, 39, 38, 37, 36, 35, 34, 33, 32, 31, 30, 29, 48, 47, 46, 45, 44, 43, 42, 41, 56, 55, 54, 53, 52, 51, 50, 49, 68, 67, 66, 65, 64, 63, 62, 61, 60, 59, 58
OFFSET
1,1
COMMENTS
Also, replacing 1's by 2's and 2's by 1's in A376637(n) yields A376637(a(n)).
This sequence is a self-inverse permutation of the positive integers without fixed points.
FORMULA
EXAMPLE
The first terms, alongside the corresponding terms from A376637 and their run lengths transform, are:
n a(n) A376637(n) A376637(a(n)) RL
-- ---- ---------- ------------- ---
1 2 1 2 1
2 1 2 1 1
3 6 11 22 2
4 5 12 21 11
5 4 21 12 11
6 3 22 11 2
7 10 112 221 21
8 9 122 211 12
9 8 211 122 12
10 7 221 112 21
11 16 1121 2212 211
12 15 1122 2211 22
13 14 1211 2122 112
14 13 2122 1211 112
15 12 2211 1122 22
16 11 2212 1121 211
PROG
(PARI) \\ See Links section.
CROSSREFS
Sequence in context: A351385 A090665 A347952 * A361198 A359806 A346306
KEYWORD
nonn,base
AUTHOR
Rémy Sigrist, Oct 01 2024
STATUS
approved