cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A303835 Number of noncrossing path sets on n nodes up to rotation and reflection with isolated vertices allowed.

Original entry on oeis.org

1, 1, 2, 3, 8, 19, 64, 212, 833, 3360, 14476, 63848, 289892, 1338000, 6275589, 29791100, 142973014, 692507861, 3382070233, 16638445745, 82395500651, 410463736691, 2055858519575, 10347925039015, 52321093290715, 265648012207312, 1353953547877556, 6925400869302520
Offset: 0

Views

Author

Andrew Howroyd, May 01 2018

Keywords

Examples

			Case n=3: There are 3 possibilities:
.
     o        o       o
                     / \
   o   o    o---o   o   o
.
Case n=4: There are 8 possibilities:
.
   o   o    o   o    o   o    o   o    o   o    o---o    o   o    o---o
                       /      |          /               |   |      /
   o   o    o---o    o   o    o---o    o---o    o---o    o---o    o---o
.
		

Crossrefs

Programs

  • PARI
    \\ See A303731 for NCPathSetsModDihedral
    Vec(NCPathSetsModDihedral(vector(30, k, 1)))