200322

Python


A333439等

Graphillion を使って計算してみた。

from graphillion import GraphSet
import graphillion.tutorial as tl

def A(start, goal, n):
    if n == 1: return 1
    universe = tl.grid(n - 1, n - 1)
    GraphSet.set_universe(universe)
    paths = GraphSet.paths(start, goal)
    return paths.len()

print([A(1,     2, n) for n in range(2, 10)])
print([A(1, n + 1, n) for n in range(2, 10)])
print([A(1,     n, n) for n in range(1, 10)])
print([A(1, n * n, n) for n in range(1, 10)])

出力結果
[2, 8, 98, 4112, 532270, 212372938, 263708907212, 1013068026356376]
[2, 8, 98, 4112, 532270, 212372938, 263708907212, 1013068026356376]
[1, 2, 11, 178, 8590, 1246850, 550254085, 741333619848, 3046540983075504]
[1, 2, 12, 184, 8512, 1262816, 575780564, 789360053252, 3266598486981642]