|
|
A289597
|
|
Related to number of mesh patterns of length 2 that avoid the pattern 321.
|
|
0
|
|
|
1, 1, 1, 2, 6, 21, 75, 266, 938, 3305, 11679
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,4
|
|
LINKS
|
|
|
FORMULA
|
G.f.: x*(1-x)*C(x) + x^2*(x^2-3*x+1)/((x-1)*(2*x-1)) (conjectured), where C(x) is the g.f. for the Catalan numbers (A000108). - Michael D. Weiner, Jan 02 2019
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn,more
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|