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A123789
Number of ways, counted up to symmetry, to build a contiguous building with n LEGO blocks of size 1 X 5 which is flat, i.e., with all blocks in parallel position and symmetric after a rotation by 180 degrees.
0
1, 1, 5, 7, 49, 77, 572, 949, 7245, 12361, 96063, 167564, 1313467, 2327488, 18365795, 32936281, 261111133, 472694546
OFFSET
1,3
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Søren Eilers, Oct 29 2006
EXTENSIONS
More terms by Søren Eilers, Sep 12 2018
STATUS
approved