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A209656
Meandric numbers for a river crossing up to 12 parallel roads at n points.
20
1, 1, 2, 4, 10, 23, 63, 155, 448, 1152, 3452, 9158, 28178, 76538, 240368, 665100, 2123379, 5964156, 19301178, 54890366, 179679030
OFFSET
0,3
COMMENTS
Number of ways that a river (or directed line) that starts in the South and flows East can cross up to 12 parallel East-West roads n times.
Sequence derived from list of solutions described in A206432.
CROSSREFS
Cf. A005316 (sequence for one road; extensive references and links).
Cf. A076876 (sequence for two parallel roads).
Cf. A206432 (sequence for unlimited number of parallel roads).
Sequence in context: A209621 A209622 A209626 * A209657 A209660 A209707
KEYWORD
nonn,more
AUTHOR
Robert Price, May 07 2012
STATUS
approved