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A357810
Number of n-step closed paths on the Cairo pentagonal lattice graph starting from a degree-4 node.
1
1, 0, 4, 0, 24, 8, 164, 136, 1236, 1704, 10116, 19144, 88616, 205208, 818764, 2155160, 7873440, 22463400, 77954740, 233894600, 788314984, 2440865400, 8095906076, 25569342520, 84107990356, 269034666280
OFFSET
0,3
EXAMPLE
For n=2, the a(2) = 4 solutions visit one of the four vertices adjacent to the initial vertex, and then return.
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.
CROSSREFS
The accompanying sequences for the number of paths that return to a degree-3 node is A357811.
Similar sequences for square, hexagonal, and honeycomb lattices are A002894, A002898 and A002893.
Sequence in context: A243270 A242027 A329891 * A057402 A269214 A269276
KEYWORD
nonn,easy,walk
AUTHOR
Dave R.M. Langers, Oct 13 2022
STATUS
approved