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A333438 Number of self-avoiding walks of any length from NW corner to its adjacent points on an n X n grid or lattice. 3
4, 16, 196, 8224, 1064540, 424745876, 527417814424, 2026136052712752 (list; graph; refs; listen; history; text; internal format)
OFFSET

2,1

COMMENTS

From Seiichi Manyama, Apr 07 2020: (Start)

a(11) = 864203211903812503254788.

a(13) = 32299777937527326896385272155961508. (End)

LINKS

Table of n, a(n) for n=2..9.

EXAMPLE

a(2) = 4;

   S--E   S  E

          |  |

          *--*

   S      S--*

   |         |

   E      E--*

a(3) = 16;

   S--E      S  E      S  E--*   S  E--*

             |  |      |     |   |     |

             *--*      *--*--*   *     *

                                 |     |

                                 *--*--*

   S  E      S  E--*   S  E--*   S  E

   |  |      |     |   |     |   |  |

   *  *      *  *--*   *--*  *   *  *--*

   |  |      |  |         |  |   |     |

   *--*      *--*         *--*   *--*--*

   S         S--*      S--*      S--*--*

   |            |         |            |

   E         E--*      E  *      E     *

                       |  |      |     |

                       *--*      *--*--*

   S--*--*   S--*--*   S--*      S--*--*

         |         |      |            |

   E--*--*   E  *--*   E  *--*   E--*  *

             |  |      |     |      |  |

             *--*      *--*--*      *--*

PROG

(Python)

# Using graphillion

from graphillion import GraphSet

import graphillion.tutorial as tl

def A333438(n):

    universe = tl.grid(n - 1, n - 1)

    GraphSet.set_universe(universe)

    start, goal = 1, 2

    paths = GraphSet.paths(start, goal)

    return paths.len() * 2

print([A333438(n) for n in range(2, 10)])

CROSSREFS

Cf. A271507, A333439.

Sequence in context: A000513 A088027 A271267 * A232840 A113905 A200045

Adjacent sequences:  A333435 A333436 A333437 * A333439 A333440 A333441

KEYWORD

nonn,more

AUTHOR

Seiichi Manyama, Mar 21 2020

STATUS

approved

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Last modified August 11 07:36 EDT 2022. Contains 356055 sequences. (Running on oeis4.)