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%I #13 Mar 28 2020 05:20:27
%S 1,1,128,624,28417,286395,8261289,114243216,2688307514,43598351250,
%T 928370853748,16331387665387,330593938169845,6062963019120077,
%U 119575303856316650,2240422461856052342,43592076562463162280,825830699757513748579,15955080499901505066753
%N Number of Hamiltonian paths in a 9 X n grid starting at the lower left corner and finishing in the upper right corner.
%H Seiichi Manyama, <a href="/A333584/b333584.txt">Table of n, a(n) for n = 1..200</a>
%H <a href="/index/Gra#graphs">Index entries for sequences related to graphs, Hamiltonian</a>
%o (Python)
%o # Using graphillion
%o from graphillion import GraphSet
%o import graphillion.tutorial as tl
%o def A333580(n, k):
%o if n == 1 or k == 1: return 1
%o universe = tl.grid(n - 1, k - 1)
%o GraphSet.set_universe(universe)
%o start, goal = 1, k * n
%o paths = GraphSet.paths(start, goal, is_hamilton=True)
%o return paths.len()
%o def A333584(n):
%o return A333580(n, 9)
%o print([A333584(n) for n in range(1, 20)])
%Y Row n=9 of A333580.
%Y Cf. A014584.
%K nonn
%O 1,3
%A _Seiichi Manyama_, Mar 27 2020
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