A123813 - cp's OEIS frontend

A123813 Number of ways, counted up to symmetry, to build a contiguous building with n LEGO blocks of size 1 X 8 which is flat, i.e., with all blocks in parallel position, and symmetric after a rotation by 180 degrees.

%I A123813 #14 Sep 14 2018 03:51:03
%S A123813 1,1,9,13,153,249,3011,5209,63991,114321,1421173,2603433,32518012,
%T A123813 60650817,760402013,1437977218
%N A123813 Number of ways, counted up to symmetry, to build a contiguous building with n LEGO blocks of size 1 X 8 which is flat, i.e., with all blocks in parallel position, and symmetric after a rotation by 180 degrees.
%Y A123813 Cf. A112389, A123762 - A123827, A123829 - A123849.
%K A123813 nonn
%O A123813 1,3
%A A123813 _Søren Eilers_, Oct 29 2006
%E A123813 a(11)-a(16) from _Søren Eilers_, Sep 14 2018

cp's OEIS Frontend

A123813 Number of ways, counted up to symmetry, to build a contiguous building with n LEGO blocks of size 1 X 8 which is flat, i.e., with all blocks in parallel position, and symmetric after a rotation by 180 degrees.