A210478 Meandric numbers for a river crossing up to 17 parallel roads at n points.

1, 1, 2, 4, 10, 23, 63, 155, 448, 1152, 3452, 9158, 28178, 76539, 240370, 665129, 2123439, 5964691, 19302315, 54898415, 179696520

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 17 parallel East-West roads n times.

Sequence derived from list of solutions described in A206432.

Links

Table of n, a(n) for n=0..20.

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: A209660 A209707 A210344 * A210567 A210592 A206432

Adjacent sequences: A210475 A210476 A210477 * A210479 A210480 A210481

Keyword

nonn,more

Author

Robert Price, May 07 2012

Status

approved