%I #13 Jun 13 2015 00:54:11
%S 1,1,2,5,13,34,88,226,578,1476,3768,9620,24564,62728,160192,409096,
%T 1044744,2668048,6813600,17400400,44436688,113481248,289805440,
%U 740097568,1890041888,4826739776,12326402432
%N Number of set partitions of [n] that avoid 1231 and 1121.
%H V. Jelinek, T. Mansour, M. Shattuck, <a href="http://dx.doi.org/10.1016/j.aam.2012.09.002">On multiple pattern avoiding set partitions</a>, Adv. Appl. Math. 50 (2) (2013) 292-326, Example 4.16 H_{1121} and example 4.17 L_{1121}.
%H <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (4,-4,0,2).
%F G.f (1-x-x^2)*(1-x)^2/(1-4*x+4*x^2-2*x^4), correcting a sign in denominators of the publication.
%K nonn,easy
%O 0,3
%A _R. J. Mathar_, Jan 12 2013