A307406 Number of twisted permutations of the nonnegative integers in base 2*n+1 with an adjacency diagram as defined by Knuth in A220952.

1, 1, 5, 47

Offset: 0

Author

Georg Fischer, Apr 07 2019

Keywords

• nonn
• hard
• more

Comments

The concept of the adjacency diagram in A220952 is not limited to base 5, but can be investigated for all odd bases. In "base 1", the path consists of a single node (1,1). For base 3, there is the ternary Gray code A128173 only. A corresponding simple up-down pattern with a path (0,0), ... (0,n), (1,n), ... (1,0), (2,0), ... (n,n) can be constructed for any odd base.

Conjecture: a(4) = 673.

Links

• Georg Fischer, Repository of programs for related sequences, (gen_paths.pl)

Crossrefs

Cf. A128173 (base 3, "n"), A220952 (Knuth, base 5, "Hn"), A307403 ("Hs"), A307404 ("Ln"), A307405 ("Ls"), A300857 (base 7).

Programs

Perl

cf. link