A102127 Interval between successive arrivals at the origin of an LQTL CA.
4, 4, 4, 16, 4, 4, 4, 16, 4, 4, 4, 4, 4, 40, 4, 16, 4, 4, 4, 4, 12, 4, 4, 8, 4, 40, 4, 4, 4, 4, 4, 88, 4, 40, 4, 4, 4, 4, 4, 16, 4, 4, 4, 16, 4, 4, 4, 4, 4, 40, 4, 88, 4, 4, 4, 4, 4, 40, 4, 8, 4, 12, 4, 4, 4, 4, 4, 16, 4, 40, 4, 4, 4, 4, 4, 16, 4, 4, 4, 16, 4
Offset: 0
Keywords
Links
- Andrey Zabolotskiy, Table of n, a(n) for n = 0..999
- Robert H. Barbour, Two-dimensional Four Color Cellular Automaton: Surface Explorations, Complex Systems, 17 (2007), 103-112.
- Palash Sarkar, A Brief History of Cellular Automata, ACM Computing Surveys, Vol. 32, No. 1, March 2000, 80-107.
Programs
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Python
x = y = direction = 0 cells, a = {}, [] for n in range(1, 1000): c = cells.get((x, y), 0) cells[(x, y)] = (c + 1) % 4 direction += [1, 1, -1, -1][c] (dx, dy) = [(1, 0), (0, 1), (-1, 0), (0, -1)][direction%4] x += dx; y += dy if (x, y) == (0, 0): a.append(n) print(a) # A102110 print([x-y for x, y in zip(a, [0]+a)]) # this sequence - Andrey Zabolotskiy, Jan 06 2023
Extensions
Terms a(26) and beyond from Andrey Zabolotskiy, Jan 06 2023
Comments