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A209707
Meandric numbers for a river crossing up to 15 parallel roads at n points.
18
1, 1, 2, 4, 10, 23, 63, 155, 448, 1152, 3452, 9158, 28178, 76539, 240370, 665129, 2123438, 5964689, 19302281, 54898345, 179695808
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 15 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: A209656 A209657 A209660 * A210344 A210478 A210567
KEYWORD
nonn,more
AUTHOR
Robert Price, May 07 2012
STATUS
approved