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%I #8 Apr 23 2015 12:32:29
%S 1,2,1,9,6,2,54,40,20,5,378,295,175,70,14,2916,2346,1526,756,252,42,
%T 24057,19739,13587,7602,3234,924,132,208494,173426,123978,74964,36828,
%U 13728,3432,429
%N Triangle read by rows: T(n,k) = number of normal planar lambda terms of size n with k free variables (n >= 1, 1 <= k <= n).
%H Noam Zeilberger, Alain Giorgetti, <a href="http://arxiv.org/abs/1408.5028">A correspondence between rooted planar maps and normal planar lambda terms</a>, arXiv:1408.5028 [cs.LO], 2014.
%e Triangle begins:
%e 1
%e 2,1
%e 9,6,2
%e 54,40,20,5
%e 378,295,175,70,14
%e 2916,2346,1526,756,252,42
%e 24057,19739,13587,7602,3234,924,132,
%e 208494,173426,123978,74964,36828,13728,3432,429
%e ...
%Y Cf. A000108, A000984, A000168, A246322.
%K nonn,tabl
%O 1,2
%A _N. J. A. Sloane_, Aug 28 2014
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