cp's OEIS Frontend

A333604 Number of directed Hamiltonian walks from NW to SW corners of an 8 X n grid.

%I A333604 #20 Jun 25 2023 21:08:55
%S A333604 1,1,64,264,6820,52387,909009,8934966,130373192,1440623260,
%T A333604 19338414411,226336038320,2916455246831,35119270968805,
%U A333604 443497762883269,5416278334971240,67721300861621626,832844111255909543,10362230473284966919
%N A333604 Number of directed Hamiltonian walks from NW to SW corners of an 8 X n grid.
%H A333604 Ed Wynn, <a href="/A333604/b333604.txt">Table of n, a(n) for n = 1..89</a>
%o A333604 (Python)
%o A333604 # Using graphillion
%o A333604 from graphillion import GraphSet
%o A333604 import graphillion.tutorial as tl
%o A333604 def A271592(n, k):
%o A333604     if k == 1: return 1
%o A333604     universe = tl.grid(k - 1, n - 1)
%o A333604     GraphSet.set_universe(universe)
%o A333604     start, goal = 1, n
%o A333604     paths = GraphSet.paths(start, goal, is_hamilton=True)
%o A333604     return paths.len()
%o A333604 def A333604(n):
%o A333604     return A271592(8, n)
%o A333604 print([A333604(n) for n in range(1, 9)])
%Y A333604 Row n=8 of A271592.
%Y A333604 Cf. A333583.
%K A333604 nonn
%O A333604 1,3
%A A333604 _Seiichi Manyama_, Mar 28 2020
%E A333604 More terms from _Ed Wynn_, Jun 25 2023