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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.
0
1, 1, 7, 10, 100, 160, 1688, 2853, 30903, 53721, 592395, 1053025, 11711448, 21151575, 236789391, 432872895
OFFSET
1,3
CROSSREFS
KEYWORD
nonn
AUTHOR
Søren Eilers, Oct 29 2006
EXTENSIONS
a(11)-a(16) from Søren Eilers, Sep 14 2018
STATUS
approved