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A057423
Diagonally symmetric n-celled polyominoes with 1 hole.
0
1, 0, 5, 4, 20, 18, 79, 84, 304, 332, 1149, 1309, 4312, 5005, 16136, 19049, 60347, 71979, 225867, 271781, 846667, 1025315, 3179798, 3871607, 11966976, 14633947, 45131841, 55395495, 170560833, 210008554, 645861961, 797419730, 2450316125, 3032540599
OFFSET
7,3
COMMENTS
The sequence refers to polyominoes with one hole and precisely one diagonal symmetry. - John Mason, Jan 16 2023
CROSSREFS
Cf. A056881.
Sequence in context: A246326 A272506 A070374 * A327317 A215139 A320799
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Sep 05 2000
EXTENSIONS
a(29)-a(49) from John Mason, Jan 16 2023
STATUS
approved