%I #10 Dec 05 2022 04:43:20
%S 6,84,5904,1064304,402671760,273315542400
%N Number of 3 X n whirlpool permutations (see A334518).
%H D. E. Knuth, <a href="https://cs.stanford.edu/~knuth/papers/whirlpool.pdf">Whirlpool Permutations</a>, May 05 2020
%Y Cf. A000142 (1 X n), A261683 (2 X n), A334517 (n X n), A334518 and A334519 (m X n).
%K nonn,more
%O 1,1
%A _N. J. A. Sloane_, May 06 2020