A209622 Meandric numbers for a river crossing up to 10 parallel roads at n points.

1, 1, 2, 4, 10, 23, 63, 155, 448, 1152, 3452, 9157, 28176, 76514, 240318, 664718, 2122557, 5959052, 19289899, 54828151, 179538447, 515641437, 1705240090, 4941294887, 16481424379, 48127922888, 161736798007, 475487875843, 1608541737898, 4757151493126, 16188528696215

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 10 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..36

Crossrefs

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: A208453 A209383 A209621 * A209626 A209656 A209657

Adjacent sequences: A209619 A209620 A209621 * A209623 A209624 A209625

Keyword

nonn

Author

Robert Price, May 07 2012

Extensions

a(21)-a(36) from Andrew Howroyd, Dec 06 2015

Status

approved