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%I #7 Sep 19 2022 14:57:29
%S 1,1,1,2,3,4,6,9,14,21,31,47,71,106,159,239,358,537,806,1209,1813,
%T 2719,4079,6119
%N Number of nodes at level n in the tree T_{-2}.
%C First differences of A355909.
%H Don Knuth, <a href="http://cs.stanford.edu/~knuth/papers/ambidextrous.pdf">Ambidextrous Numbers</a>, Preprint, September 2022. See (12.6).
%Y Cf. A355904-A355909, A355911-A355913.
%K nonn,more
%O 0,4
%A _N. J. A. Sloane_, Sep 19 2022