17920860

Appears in sequences

• Number of necklaces with n beads of 2 colors, allowing turning over (these are also called bracelets).at n=30A000029
• Number of n-bead necklaces of 3 colors allowing reversal, with no adjacent beads having the same color.at n=29A208539
• Number of toroidal n X 2 binary arrays, allowing rotation and/or reflection of the rows and/or the columns.at n=14A222187