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 A333246 Number of self-avoiding closed paths on an n X n grid which pass through NW corner. 6
 1, 7, 97, 4111, 532269, 212372937, 263708907211, 1013068026356375 (list; graph; refs; listen; history; text; internal format)
 OFFSET 2,2 COMMENTS From Seiichi Manyama, Apr 07 2020: (Start) a(11) = 432101605951906251627393. a(13) = 16149888968763663448192636077980753. (End) LINKS FORMULA a(n) = A333439(n) - 1 for n > 1. EXAMPLE a(2) = 1;    +--*    |  |    *--* a(3) = 7;    +--*      +--*--*   +--*--*   +--*    |  |      |     |   |     |   |  |    *--*      *--*--*   *     *   *  *                        |     |   |  |                        *--*--*   *--*    +--*--*   +--*--*   +--*    |     |   |     |   |  |    *  *--*   *--*  *   *  *--*    |  |         |  |   |     |    *--*         *--*   *--*--* PROG (Python) # Using graphillion from graphillion import GraphSet import graphillion.tutorial as tl def A333246(n):     universe = tl.grid(n - 1, n - 1)     GraphSet.set_universe(universe)     cycles = GraphSet.cycles().including(1)     return cycles.len() print([A333246(n) for n in range(2, 10)]) CROSSREFS Cf. A140517, A333247, A333323, A333438, A333439, A333466. Sequence in context: A046908 A005014 A201063 * A335922 A157035 A022008 Adjacent sequences:  A333243 A333244 A333245 * A333247 A333248 A333249 KEYWORD nonn,more AUTHOR Seiichi Manyama, Mar 23 2020 STATUS approved

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Last modified April 22 22:19 EDT 2021. Contains 343197 sequences. (Running on oeis4.)