A123805 - cp's OEIS frontend

A123805 Number of ways, counted up to symmetry, to build a contiguous building with n LEGO blocks of size 1 X 7 which is flat, i.e., with all blocks in parallel position, and symmetric after a rotation by 180 degrees.

%I A123805 #14 Sep 14 2018 03:51:23
%S A123805 1,1,7,10,100,160,1688,2853,30903,53721,592395,1053025,11711448,
%T A123805 21151575,236789391,432872895
%N A123805 Number of ways, counted up to symmetry, to build a contiguous building with n LEGO blocks of size 1 X 7 which is flat, i.e., with all blocks in parallel position, and symmetric after a rotation by 180 degrees.
%Y A123805 Cf. A112389, A123762 - A123827, A123829 - A123849.
%K A123805 nonn
%O A123805 1,3
%A A123805 _Søren Eilers_, Oct 29 2006
%E A123805 a(11)-a(16) from _Søren Eilers_, Sep 14 2018

cp's OEIS Frontend

A123805 Number of ways, counted up to symmetry, to build a contiguous building with n LEGO blocks of size 1 X 7 which is flat, i.e., with all blocks in parallel position, and symmetric after a rotation by 180 degrees.