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A209657
Meandric numbers for a river crossing up to 13 parallel roads at n points.
18
1, 1, 2, 4, 10, 23, 63, 155, 448, 1152, 3452, 9158, 28178, 76539, 240369, 665127, 2123408, 5964627, 19301713, 54897139, 179687084
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 13 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: A209622 A209626 A209656 * A209660 A209707 A210344
KEYWORD
nonn,more
AUTHOR
Robert Price, May 07 2012
STATUS
approved