login
A208126
Meandric numbers for a river crossing up to 5 parallel roads at n points.
18
1, 1, 2, 4, 10, 23, 62, 153, 433, 1120, 3281, 8776, 26399, 72423, 222496, 622616, 1946044, 5533227, 17545134, 50545069, 162237507, 472541542, 1532707268, 4506042037, 14748997812, 43709690021, 144213436887, 430371626111, 1429980808522, 4293569179189, 14355812667699
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 5 parallel East-West roads n times.
Sequence derived from list of solutions described in A206432.
LINKS
CROSSREFS
Cf. A005316 (sequence for one road; extensive references and links).
Cf. A076876 (sequence for two parallel roads).
Cf. A206432 (sequence for unlimited number of parallel roads).
Sequence in context: A354076 A151256 A205999 * A370646 A208452 A208453
KEYWORD
nonn
AUTHOR
Robert Price, May 07 2012
EXTENSIONS
a(21)-a(36) from Andrew Howroyd, Dec 05 2015
STATUS
approved