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A216718 Triangle read by rows: number of circular permutations of [1..n] with k progressions of rise 1, distance 1 and length 3 (n >= 3, k >= 0). 6
1, 1, 1, 5, 0, 1, 20, 3, 0, 1, 102, 14, 3, 0, 1, 627, 72, 17, 3, 0, 1, 4461, 468, 87, 20, 3, 0, 1, 36155, 3453, 582, 103, 23, 3, 0, 1, 328849, 28782, 4395, 704, 120, 26, 3, 0, 1, 3317272, 267831, 37257, 5435, 834, 138, 29, 3, 0, 1 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

2,4

REFERENCES

Wayne M. Dymacek, Isaac Lambert and Kyle Parsons, Arithmetic Progressions in Permutations, http://math.ku.edu/~ilambert/CN.pdf, 2012.

LINKS

Table of n, a(n) for n=2..56.

EXAMPLE

Triangle begins:

        1;

        1,      1; [this is row n=3]

        5,      0,     1;

       20,      3,     0,    1;

      102,     14,     3,    0,   1;

      627,     72,    17,    3,   0,   1;

     4461,    468,    87,   20,   3,   0,  1;

    36155,   3453,   582,  103,  23,   3,  0, 1;

   328849,  28782,  4395,  704, 120,  26,  3, 0, 1;

  3317272, 267831, 37257, 5435, 834, 138, 29, 3, 0, 1;

  ...

CROSSREFS

Cf. A216716, A174072, A165961, A180187.

Sequence in context: A345453 A064315 A227322 * A184180 A256069 A267480

Adjacent sequences:  A216715 A216716 A216717 * A216719 A216720 A216721

KEYWORD

nonn,tabl

AUTHOR

N. J. A. Sloane, Sep 15 2012

EXTENSIONS

a(2,0)=1 added by N. J. A. Sloane, Apr 16 2021

STATUS

approved

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Last modified November 30 18:40 EST 2021. Contains 349424 sequences. (Running on oeis4.)