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A338403 Regular triangle read by rows: T(n,k) is the number of (n,k)-Duck words, for n>=1 and 0<=k<=n-1. 0
1, 2, 3, 5, 23, 14, 14, 131, 233, 84, 42, 664, 2339, 2367, 594, 132, 3166, 18520, 36265, 24714, 4719, 429, 14545, 127511, 408311, 527757, 266219, 40898 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

See link for the definition of Duck word.

LINKS

Table of n, a(n) for n=1..28.

Ilani Axelrod-Freed, 312-Avoiding Reduced Valid Hook Configurations and Duck Words, arXiv:2010.11834 [math.CO], 2020. See Definition 5.1 p. 11.

EXAMPLE

Triangle begins:

   1;

   2,   3;

   5,  23,   14;

  14, 131,  233,   84;

  42, 664, 2339, 2367, 594;

  ...

CROSSREFS

Cf. A000108 (column 0), A005700 (diagonal), A005789 (row sums), A031970 (column 1).

Sequence in context: A013639 A047995 A244862 * A024782 A024775 A024767

Adjacent sequences:  A338400 A338401 A338402 * A338404 A338405 A338406

KEYWORD

nonn,tabl,more

AUTHOR

Michel Marcus, Oct 24 2020

STATUS

approved

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Last modified May 20 21:39 EDT 2022. Contains 353876 sequences. (Running on oeis4.)