

A209383


Meandric numbers for a river crossing up to 8 parallel roads at n points.


18



1, 1, 2, 4, 10, 23, 63, 155, 448, 1151, 3450, 9137, 28134, 76236, 239712, 661374, 2115046, 5921549, 19203568, 54422726, 178585838, 511343777, 1694965469, 4896195579, 16371992897, 47656781437, 160578870274, 470571482142, 1596323368095, 4705798878362, 16059653893209
(list;
graph;
refs;
listen;
history;
text;
internal format)



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 8 parallel EastWest 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: A208126 A208452 A208453 * A209621 A209622 A209626
Adjacent sequences: A209380 A209381 A209382 * A209384 A209385 A209386


KEYWORD

nonn


AUTHOR

Robert Price, May 07 2012


EXTENSIONS

a(21)a(36) from Andrew Howroyd, Dec 05 2015


STATUS

approved



