A209657 - OEIS

%I #16 May 08 2012 00:00:38

%S 1,1,2,4,10,23,63,155,448,1152,3452,9158,28178,76539,240369,665127,

%T 2123408,5964627,19301713,54897139,179687084

%N Meandric numbers for a river crossing up to 13 parallel roads at n points.

%C Number of ways that a river (or directed line) that starts in the South and flows East can cross up to 13 parallel East-West roads n times.

%C Sequence derived from list of solutions described in A206432.

%Y Cf. A005316 (sequence for one road; extensive references and links).

%Y Cf. A076876 (sequence for two parallel roads).

%Y 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).

%Y Cf. A206432 (sequence for unlimited number of parallel roads).

%Y Cf. A076875, A076906, A076907.

%K nonn,more

%O 0,3

%A _Robert Price_, May 07 2012