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%I #8 Mar 03 2017 19:40:24
%S 1,3,9,25,69,192,537,1508,4249,12009,34044,96795,275989,789040,
%T 2261594,6497986,18712521,54002913,156162531,452435327,1313117536,
%U 3817402150,11114803333,32408592752,94623871921,276620070867,809602760028,2372089156969,6957106088502,20423727601032,60009849519354
%N a(n) = number of n-lettered words in the alphabet {1, 2, 3} with as many occurrences of the substring (consecutive subword) [1, 1, 2] as of [1, 3, 1].
%H Shalosh B. Ekhad and Doron Zeilberger, <a href="http://arxiv.org/abs/1112.6207">Automatic Solution of Richard Stanley's Amer. Math. Monthly Problem #11610 and ANY Problem of That Type</a>, arXiv preprint arXiv:1112.6207, 2011. See subpages for rigorous derivations of g.f., recurrence, asymptotics for this sequence.
%K nonn
%O 0,2
%A _N. J. A. Sloane_, Apr 07 2012
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