A060135 - cp's OEIS frontend

A060135 Sequence of adjacent transpositions (a[n] a[n]+1), which, when starting from the identity permutation and applied successively, produce a Hamiltonian circuit through all permutations of S_4, in such a way that S_{n-1} is always traversed before the rest of S_n. Furthermore, each subsequence from the first to the (n!-1)-th term is palindromic.

n	a(n)
0	1
1	2
2	1
3	2
4	1
5	3
6	1
7	2
8	3
9	2
10	1
11	2
12	1
13	2
14	3
15	2
16	1
17	3
18	1
19	2
20	1
21	2
22	1

[1, 2, 1, 2, 1, 3, 1, 2, 3, 2, 1, 2, 1, 2, 3, 2, 1, 3, 1, 2, 1, 2, 1]