933458

Appears in sequences

• Closed meandric numbers (or meanders): number of ways a loop can cross a road 2n times.at n=9A005315
• Meandric numbers: number of ways a river can cross a road n times.at n=17A005316
• Triangle read by rows: T(n,k) = number of closed meander systems of order n with k<=n components.at n=36A008828
• Number of ways that a directed line (or river) that starts in the south can cross an east-west road n times.at n=17A077014
• G.f. satisfies: A(x) = Sum_{n>=0} x^n * Product_{d|n} A(x^d)^(n/d).at n=13A206302
• Triangle read by rows: T(n,k) is the number of closed forest meander systems with 2n crossings and k components.at n=46A380368