A210344 Meandric numbers for a river crossing up to 16 parallel roads at n points.

1, 1, 2, 4, 10, 23, 63, 155, 448, 1152, 3452, 9158, 28178, 76539, 240370, 665129, 2123439, 5964690, 19302314, 54898380, 179696483, 516468114, 1707135091, 4950691884, 16503311633, 48232404028, 161983554724, 476633293902, 1611280036392, 4769597694865, 16218604538134

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 16 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=16 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: A209657 A209660 A209707 * A210478 A210567 A210592

Adjacent sequences: A210341 A210342 A210343 * A210345 A210346 A210347

Keyword

nonn

Author

Robert Price, May 07 2012

Extensions

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

Status

approved