A123797 - OEIS

A123797

Number of ways, counted up to symmetry, to build a contiguous building with n LEGO blocks of size 1 X 6 which is flat, i.e., with all blocks in parallel position and symmetric after a rotation by 180 degrees.

%I #12 Sep 12 2018 05:30:11

%S 1,1,7,10,88,142,1277,2193,19967,35449,325809,593589,5473435,10159187,

%T 93929982,176846933

%N Number of ways, counted up to symmetry, to build a contiguous building with n LEGO blocks of size 1 X 6 which is flat, i.e., with all blocks in parallel position and symmetric after a rotation by 180 degrees.

%Y Cf. A112389, A123762 - A123827, A123829 - A123849.

%K nonn,more

%O 1,3

%A _Søren Eilers_, Oct 29 2006

%E More terms by _Søren Eilers_, Sep 12 2018