A285916 Self-inverse permutation: in base 3, reverse the lengths of runs of consecutive equal digits.

0, 1, 2, 3, 4, 5, 6, 7, 8, 12, 10, 11, 9, 13, 17, 15, 16, 14, 24, 19, 20, 21, 25, 23, 18, 22, 26, 39, 28, 29, 30, 37, 32, 33, 34, 38, 36, 31, 35, 27, 40, 53, 45, 49, 44, 42, 46, 47, 48, 43, 50, 51, 52, 41, 78, 55, 56, 57, 73, 59, 60, 61, 74, 75, 64, 65, 66, 79

Offset: 0

Author

Rémy Sigrist, Apr 28 2017

Keywords

• nonn
• base
• look

Comments

This sequence can be seen as an analog of A056539 for the base 3.

For any n>=0, n and a(n) have the same number of digits in base 3.

Examples

			The first terms for which n<>a(n) are:
Decimal:    Base 3:
n   a(n)    n       a(n)
-   ----    ---     ----
9   12      100     110
12  9       110     100
14  17      112     122
17  14      122     112
18  24      200     220
22  25      211     221
24  18      220     200
25  22      221     211
27  39      1000    1110
31  37      1011    1101
35  38      1022    1102
37  31      1101    1011
38  35      1102    1022
39  27      1110    1000
41  53      1112    1222
42  45      1120    1200
		

Links

• Rémy Sigrist, Table of n, a(n) for n = 0..6560
• Rémy Sigrist, PARI program for A285916
• Index entries for sequences that are permutations of the natural numbers

Crossrefs

Cf. A056539.