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A220514
D-toothpick sequence of the third kind starting with a X-shaped cross formed by 4 D-toothpicks.
6
0, 4, 12, 28, 44, 60, 92, 136, 168, 184, 216, 280, 376, 440, 520, 620, 684, 700, 732, 796, 892, 1020, 1164, 1332, 1508, 1588, 1684, 1860, 2116, 2276, 2452, 2664, 2792, 2808, 2840, 2904, 3000, 3128, 3272, 3448, 3656, 3824, 4016, 4272, 4676, 4992
OFFSET
0,2
COMMENTS
This is a toothpick sequence of forking paths to 135 degrees. The sequence gives the number of toothpicks and D-toothpicks in the structure after n-th stage. A221528 (the first differences) give the number of toothpicks or D-toothpicks added at n-th stage. It appears that the structure has a fractal (or fractal-like) behavior. For more information see A194700.
First differs from A194434 at a(13).
FORMULA
a(n) = 4*A220524(n).
KEYWORD
nonn
AUTHOR
Omar E. Pol, Dec 15 2012
STATUS
approved