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%I #9 Nov 29 2017 03:37:46
%S 2,28,104,1783,9593,187265,1093734
%N Number of ways to build a contiguous building with n LEGO blocks of size 1 X 7 on top of a fixed block of the same size so that the building is symmetric after a rotation by 180 degrees.
%C The base block is not counted among the n and must be the only block in the bottom layer of the building.
%Y Cf. A112389, A123762 - A123827, A123829 - A123849.
%K nonn,more
%O 1,1
%A _Søren Eilers_, Oct 29 2006
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