A376686 - OEIS

%I #8 Oct 03 2024 11:03:38

%S 1,2,3,5,4,6,10,8,12,7,11,9,15,21,13,19,17,18,16,22,14,20,23,32,28,30,

%T 35,25,33,26,34,24,29,31,27,36,46,53,50,40,52,44,48,42,54,37,49,43,47,

%U 39,51,41,38,45,60,76,66,63,79,55,71,65,58,74,62,57,67

%N a(n) is the unique k such that A376677(k) is the reversal of A376677(n), or -1 if no such k exists.

%C Is this sequence a permutation of the positive integers?

%H Rémy Sigrist, <a href="/A376686/b376686.txt">Table of n, a(n) for n = 1..10304</a>

%H Rémy Sigrist, <a href="/A376686/a376686.gp.txt">PARI program</a>

%H <a href="/index/K#Kolakoski">Index entries for sequences related to Kolakoski sequence</a>

%e The first terms, alongside the corresponding terms of A376677, are:

%e   n   a(n)  A376677(n)  A376677(a(n))

%e   --  ----  ----------  -------------

%e    1     1           1              1

%e    2     2           2              2

%e    3     3          11             11

%e    4     5          12             21

%e    5     4          21             12

%e    6     6          22             22

%e    7    10         112            211

%e    8     8         121            121

%e    9    12         122            221

%e   10     7         211            112

%e   11    11         212            212

%e   12     9         221            122

%e   13    15        1121           1211

%e   14    21        1122           2211

%e   15    13        1211           1121

%e   16    19        1212           2121

%o (PARI) \\ See Links section.

%Y Cf. A000002, A376677, A376685.

%K nonn,base

%O 1,2

%A _Rémy Sigrist_, Oct 01 2024