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A307406 Number of twisted permutations of the nonnegative integers in base 2*n+1 with an adjacency diagram as defined by Knuth in A220952. 3
1, 1, 5, 47 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,3
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
PROG
(Perl) cf. link
CROSSREFS
Cf. A128173 (base 3, "n"), A220952 (Knuth, base 5, "Hn"), A307403 ("Hs"), A307404 ("Ln"), A307405 ("Ls"), A300857 (base 7).
Sequence in context: A183240 A299715 A000872 * A060392 A196160 A136088
KEYWORD
nonn,hard,more
AUTHOR
Georg Fischer, Apr 07 2019
STATUS
approved

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Last modified May 26 16:22 EDT 2024. Contains 372840 sequences. (Running on oeis4.)