A186744 Number of connected regular simple graphs on n vertices with girth exactly 4.
0, 0, 0, 0, 1, 0, 1, 0, 3, 0, 8, 2, 34, 31, 330, 1607, 17970, 193906, 2867269, 32674056, 1581626328, 6705889815
Offset: 0
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