A210592 Meandric numbers for a river crossing up to 19 parallel roads at n points.

1, 1, 2, 4, 10, 23, 63, 155, 448, 1152, 3452, 9158, 28178, 76539, 240370, 665129, 2123439, 5964691, 19302316, 54898417, 179696558, 516468943, 1707136794, 4950706511, 16503342067, 48232628420, 161984027241, 476636439213, 1611286734027, 4769639146736, 16218693724179

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 19 parallel East-West roads n times.

Sequence derived from list of solutions described in A206432.

Links

Andrew Howroyd, Table of n, a(n) for n = 0..40

Crossrefs

Column k=19 of A380367.

Cf. A005316 (sequence for one road; extensive references and links).

Cf. A076876 (sequence for two parallel roads).

Cf. A204352, A208062, A208126, A208452, A208453, A209383, A209621, A209622, A209626, A209656, A209657, A209660, A209707, A210344, A210478, A210567, A210592 (sequences for 3 to 19 parallel roads).

Cf. A206432 (sequence for unlimited number of parallel roads).

Cf. A076875, A076906, A076907.

Sequence in context: A210344 A210478 A210567 * A206432 A124480 A337179

Adjacent sequences: A210589 A210590 A210591 * A210593 A210594 A210595

Keyword

nonn

Author

Robert Price, May 07 2012

Extensions

a(21) onwards from Andrew Howroyd, Jan 31 2025

Status

approved