%I #15 Feb 13 2024 09:56:57
%S 1,1,1,3,4,2,14,20,15,5,83,120,105,56,14,570,820,770,504,210,42,4318,
%T 6152,5985,4368,2310,792,132,35068,49448,49014,38136,23100,10296,3003,
%U 429
%N Triangle read by rows: T(n,k) = number of neutral planar lambda terms of size n with k free variables (n >= 0, 1 <= k <= n+1).
%H Noam Zeilberger and 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 1,1
%e 3,4,2
%e 14,20,15,5
%e 83,120,105,56,14,
%e 570,820,770,504,210,42
%e 4318,6152,5985,4368,2310,792,132
%e 35068,49448,49014,38136,23100,10296,3003,429
%e ...
%Y Cf. A000108, A001791, A220910, A246323.
%K nonn,tabl,more
%O 0,4
%A _N. J. A. Sloane_, Aug 28 2014