73424650

Appears in sequences

• Closed meandric numbers (or meanders): number of ways a loop can cross a road 2n times.at n=11A005315
• Meandric numbers: number of ways a river can cross a road n times.at n=21A005316
• Number of ways that a directed line (or river) that starts in the south can cross an east-west road n times.at n=21A077014