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%I #11 Nov 07 2017 18:27:35
%S 1,1,4,4,1,15,63,96,48,1,44,468,1936,3688,3264,1088,1,120,2795,23990,
%T 98275,214640,256720,158720,39680
%N Triangle T(n,k) read by rows; related to number of preorders.
%C Row n has 2n-1 entries.
%H G. Kreweras, <a href="http://www.numdam.org/item?id=MSH_1976__53__5_0">Les préordres totaux compatibles avec un ordre partiel</a>, Math. Sci. Humaines No. 53 (1976), 5-30. (The array on page 22.)
%H G. Kreweras, <a href="/A019538/a019538.pdf">Les préordres totaux compatibles avec un ordre partiel</a>, Math. Sci. Humaines No. 53 (1976), 5-30. (Annotated scanned copy)
%F How is this array defined?
%e 1; 1,4,4; 1,15,63,96,48; ...
%K nonn,tabf,more
%O 1,3
%A _N. J. A. Sloane_, Jan 21 2003