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.

Showing 1-2 of 2 results.

A121785 "Spanning walks" on the square lattice (see Jensen web site for further information).

Original entry on oeis.org

8, 95, 2320, 154259, 30549774, 17777600753, 30283708455564, 152480475641255213, 2287842813828061810244, 102744826737618542833764649, 13848270995235582268846758977770
Offset: 1

Views

Author

N. J. A. Sloane, Aug 30 2006

Keywords

Comments

Number of Hamiltonian paths in the graph P_{n+1} X P_{n+1} starting at any of the n+1 vertices on one side of the graph and terminating at any of the n+1 vertices on the opposite side. - Andrew Howroyd, Apr 10 2016

Crossrefs

A333323 Number of self-avoiding closed paths on an n X n grid which pass through NW and SE corners.

Original entry on oeis.org

1, 3, 42, 1799, 232094, 92617031, 115156685746, 442641690778179, 5224287477491915786, 188825256606226776728029, 20879416139356164466643759334, 7057757437924198729598570424130207, 7287699030020917172151307665469211016474, 22973720258279267139936821063450448822110219653
Offset: 2

Views

Author

Seiichi Manyama, Mar 23 2020

Keywords

Examples

			a(2) = 1;
   +--*
   |  |
   *--+
a(3) = 3;
   +--*--*   +--*--*   +--*
   |     |   |     |   |  |
   *--*  *   *     *   *  *--*
      |  |   |     |   |     |
      *--+   *--*--+   *--*--+
		

Crossrefs

Programs

  • Python
    # Using graphillion
    from graphillion import GraphSet
    import graphillion.tutorial as tl
    def A333323(n):
        universe = tl.grid(n - 1, n - 1)
        GraphSet.set_universe(universe)
        cycles = GraphSet.cycles().including(1).including(n * n)
        return cycles.len()
    print([A333323(n) for n in range(2, 10)])

Extensions

a(11) from Seiichi Manyama, Apr 07 2020
a(10) and a(12)-a(15) from Vaclav Kotesovec, Aug 16 2022 (computed by Anthony Guttmann)
Showing 1-2 of 2 results.