This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A339121 #12 Feb 16 2025 08:34:01 %S A339121 36,4040,542295,51139577,4237530095,345142437669,28251882697663, %T A339121 2318527339461265,190273063549680295,15609156135669687673, %U A339121 1280305089790914190288,105011610206669201362004,8613171107463963712000106,706463610718638922253288622,57945052730138702492774189915 %N A339121 Number of cycles in the grid graph P_9 X P_n. %H A339121 Seiichi Manyama, <a href="/A339121/b339121.txt">Table of n, a(n) for n = 2..150</a> %H A339121 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/GraphCycle.html">Graph Cycle</a> %H A339121 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/GridGraph.html">Grid Graph</a> %o A339121 (Python) %o A339121 # Using graphillion %o A339121 from graphillion import GraphSet %o A339121 import graphillion.tutorial as tl %o A339121 def A(n, k): %o A339121 universe = tl.grid(n - 1, k - 1) %o A339121 GraphSet.set_universe(universe) %o A339121 cycles = GraphSet.cycles() %o A339121 return cycles.len() %o A339121 def A339121(n): %o A339121 return A(n, 9) %o A339121 print([A339121(n) for n in range(2, 15)]) %Y A339121 Cf. A140517, A231829. %K A339121 nonn %O A339121 2,1 %A A339121 _Seiichi Manyama_, Nov 24 2020