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A339119 Number of cycles in the grid graph P_7 X P_n.

%I A339119 #17 Feb 16 2025 08:34:01
%S A339119 21,681,23984,692194,18438929,487150371,12947640143,345142437669,
%T A339119 9203308475041,245355064111139,6540331954247241,174341025325354201,
%U A339119 4647322411026104632,123881845810609904802,3302270967098053652763,88027348826922694314763,2346510376337057464408514
%N A339119 Number of cycles in the grid graph P_7 X P_n.
%C A339119 a(n+1) / a(n) tends to 26.65660630533835653493851570574867751479178653672292060740586256111131858... - _Vaclav Kotesovec_, Nov 24 2020
%H A339119 Seiichi Manyama, <a href="/A339119/b339119.txt">Table of n, a(n) for n = 2..500</a>
%H A339119 Vaclav Kotesovec, <a href="/A339119/a339119.txt">Empirical g.f.</a>
%H A339119 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/GraphCycle.html">Graph Cycle</a>
%H A339119 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/GridGraph.html">Grid Graph</a>
%o A339119 (Python)
%o A339119 # Using graphillion
%o A339119 from graphillion import GraphSet
%o A339119 import graphillion.tutorial as tl
%o A339119 def A(n, k):
%o A339119     universe = tl.grid(n - 1, k - 1)
%o A339119     GraphSet.set_universe(universe)
%o A339119     cycles = GraphSet.cycles()
%o A339119     return cycles.len()
%o A339119 def A339119(n):
%o A339119     return A(n, 7)
%o A339119 print([A339119(n) for n in range(2, 15)])
%Y A339119 Cf. A140517, A231829.
%K A339119 nonn
%O A339119 2,1
%A A339119 _Seiichi Manyama_, Nov 24 2020