%I #13 Sep 09 2017 03:31:38
%S 1,3,31,412,6435,106108,1825803,32320892,584956651,10772558067,
%T 201219520632
%N Number of ways, counted up to symmetry, to build a contiguous building with n LEGO blocks of size 2 X 2.
%H S. Eilers, <a href="http://www.jstor.org/stable/10.4169/amer.math.monthly.123.5.415">The LEGO counting problem</a>, Amer. Math. Mnthly, 123 (May 2016), 415-426.
%H <a href="/wiki/Index_to_OEIS:_Section_Lc#LEGO">Index entry for sequences related to LEGO blocks</a>
%Y Cf. A112389, A123762-A123827, A123829-A123849.
%K nonn,hard,more
%O 1,2
%A _Søren Eilers_, Oct 29 2006