A123804 - OEIS

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A123804

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.

%I #7 Jul 21 2017 15:39:52

%S 1,7,109,1877,35243,685817,13719483,279714347,5788634457

%N 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.

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

%K nonn,hard

%O 1,2

%A _Søren Eilers_, Oct 29 2006