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 A357810 #12 Nov 27 2022 11:32:16 %S A357810 1,0,4,0,24,8,164,136,1236,1704,10116,19144,88616,205208,818764, %T A357810 2155160,7873440,22463400,77954740,233894600,788314984,2440865400, %U A357810 8095906076,25569342520,84107990356,269034666280 %N A357810 Number of n-step closed paths on the Cairo pentagonal lattice graph starting from a degree-4 node. %H A357810 Wikipedia, <a href="https://en.wikipedia.org/wiki/Cairo_pentagonal_tiling">Cairo pentagonal tiling</a> %e A357810 For n=2, the a(2) = 4 solutions visit one of the four vertices adjacent to the initial vertex, and then return. %e A357810 For n=5, the a(5) = 8 solutions consist of counterclockwise or clockwise traversals of the circumference of any of the four pentagons that surround the initial vertex. %Y A357810 The accompanying sequences for the number of paths that return to a degree-3 node is A357811. %Y A357810 Similar sequences for square, hexagonal, and honeycomb lattices are A002894, A002898 and A002893. %K A357810 nonn,easy,walk %O A357810 0,3 %A A357810 _Dave R.M. Langers_, Oct 13 2022