|
%I #9 Apr 13 2021 19:21:24
%S 2,6,22,2,109,10,1,657,55,7,1,4625,356,54,4,1,37186,2723,362,44,4,1,
%T 336336,23300,2837,368,34,4,1,3379058,220997,25408,2967,330,35,4,1,
%U 37328103,2308564,249736,26964,3100,292,36,4,1
%N 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).
%D Wayne M. Dymacek, Isaac Lambert and Kyle Parsons, Arithmetic Progressions in Permutations, http://math.ku.edu/~ilambert/CN.pdf, 2012.
%e Triangle begins:
%e 2
%e 6
%e 22 2
%e 109 10 1
%e 657 55 7 1
%e 4625 356 54 4 1
%e 37186 2723 362 44 4 1
%e 336336 23300 2837 368 34 4 1
%e 3379058 220997 25408 2967 330 35 4 1
%e 37328103 2308564 249736 26964 3100 292 36 4 1
%e ...
%Y Columns 1..2 are A174074, A216721.
%Y Row sums are A000142(n-1).
%Y Cf. A216716, A216718.
%K nonn,tabf
%O 3,1
%A _N. J. A. Sloane_, Sep 15 2012
|
