A303844 Number of noncrossing path sets on n nodes up to rotation with each path having at least two nodes.

1, 0, 1, 1, 4, 7, 26, 69, 246, 818, 2976, 10791, 40591, 153959, 594753, 2320696, 9159498, 36467012, 146411208, 592046830, 2409946566, 9867745442, 40623068380, 168058068487, 698400767839, 2914407151002, 12208398647345, 51322369218674, 216463504458521

Offset

0,5

Links

Andrew Howroyd, Table of n, a(n) for n = 0..200

Example

Case n=4: There are 4 possibilities:
.
   o---o   o   o   o---o   o---o
           |   |     /       \
   o---o   o---o   o---o   o---o
.

Prog

(PARI) \\ See A303732 for NCPathSetsModCyclic
Vec(NCPathSetsModCyclic(vector(30, k, k>1)))

Crossrefs

Cf. A303730, A303732, A303836, A303839.

Sequence in context: A077441 A378100 A269744 * A197789 A076148 A203570

Adjacent sequences: A303841 A303842 A303843 * A303845 A303846 A303847

Keyword

nonn

Author

Andrew Howroyd, May 01 2018

Status

approved