The OEIS is supported by the many generous donors to the OEIS Foundation.
%I #12 Nov 05 2025 15:22:18
%S 1,2,4,8,14,24,44,82,152,280,522,980,1852,3506,6672,12736,24418,46916,
%T 90436,174658,338208,655936,1274786,2480740,4835588,9436162,18438560,
%U 36063040,70611906,138368900,271392388,532664834,1046273664,2056340608
%N Number of binary strings of length n with equal numbers of 0110 and 1001 substrings.
%H R. H. Hardin, <a href="/A164177/b164177.txt">Table of n, a(n) for n=0..500</a>
%H Shalosh B. Ekhad and Doron Zeilberger, <a href="https://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. [From _N. J. A. Sloane_, Apr 07 2012]
%K nonn
%O 0,2
%A _R. H. Hardin_, Aug 11 2009