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A123839
Number of ways, counted up to symmetry, to build a contiguous building with n LEGO blocks of size 4 X 4 which is symmetric after a rotation by 180 degrees.
0
1, 1, 21, 67, 1565, 6241, 137613, 630193, 13136926
OFFSET
1,3
CROSSREFS
KEYWORD
nonn
AUTHOR
Søren Eilers, Oct 29 2006
STATUS
approved