login
A303868
Triangle read by rows: T(n,k) = number of noncrossing path sets on n nodes up to rotation and reflection with k paths and isolated vertices allowed.
3
1, 1, 1, 1, 1, 1, 2, 3, 2, 1, 3, 7, 6, 2, 1, 6, 20, 23, 11, 3, 1, 10, 50, 80, 51, 17, 3, 1, 20, 136, 285, 252, 109, 26, 4, 1, 36, 346, 966, 1119, 652, 200, 36, 4, 1, 72, 901, 3188, 4782, 3623, 1502, 352, 50, 5, 1, 136, 2264, 10133, 19116, 18489, 9949, 3120, 570, 65, 5, 1
OFFSET
1,7
LINKS
EXAMPLE
Triangle begins:
1;
1, 1;
1, 1, 1;
2, 3, 2, 1;
3, 7, 6, 2, 1;
6, 20, 23, 11, 3, 1;
10, 50, 80, 51, 17, 3, 1;
20, 136, 285, 252, 109, 26, 4, 1;
36, 346, 966, 1119, 652, 200, 36, 4, 1;
72, 901, 3188, 4782, 3623, 1502, 352, 50, 5, 1;
...
PROG
(PARI) \\ See A303731 for NCPathSetsModDihedral
{ my(rows=Vec(NCPathSetsModDihedral(vector(10, k, y))-1));
for(n=1, #rows, for(k=1, n, print1(polcoeff(rows[n], k), ", ")); print; ) }
CROSSREFS
Row sums are A303835.
Column 1 is A005418(n-2).
Sequence in context: A368605 A334715 A026105 * A060475 A168069 A334014
KEYWORD
nonn,tabl
AUTHOR
Andrew Howroyd, May 01 2018
STATUS
approved