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A216719
Triangle read by rows: number of circular permutations of [1..n] with k progressions of rise 1, distance 2 and length 3 (n >= 3, k >= 0).
5
2, 6, 22, 2, 109, 10, 1, 657, 55, 7, 1, 4625, 356, 54, 4, 1, 37186, 2723, 362, 44, 4, 1, 336336, 23300, 2837, 368, 34, 4, 1, 3379058, 220997, 25408, 2967, 330, 35, 4, 1, 37328103, 2308564, 249736, 26964, 3100, 292, 36, 4, 1
OFFSET
3,1
REFERENCES
Wayne M. Dymacek, Isaac Lambert and Kyle Parsons, Arithmetic Progressions in Permutations, http://math.ku.edu/~ilambert/CN.pdf, 2012.
EXAMPLE
Triangle begins:
2
6
22 2
109 10 1
657 55 7 1
4625 356 54 4 1
37186 2723 362 44 4 1
336336 23300 2837 368 34 4 1
3379058 220997 25408 2967 330 35 4 1
37328103 2308564 249736 26964 3100 292 36 4 1
...
CROSSREFS
Columns 1..2 are A174074, A216721.
Row sums are A000142(n-1).
Sequence in context: A216964 A187250 A129534 * A085286 A062085 A284632
KEYWORD
nonn,tabf
AUTHOR
N. J. A. Sloane, Sep 15 2012
STATUS
approved