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A151885
Similar to the original toothpick sequence A139250, except that the rule is now: a toothpick changes state if its midpoint is adjacent to exactly one ON toothpick.
4
0, 1, 3, 5, 11, 5, 15, 17, 39, 5, 15, 25, 55, 17, 51, 61, 139, 5, 15, 25, 55, 25, 75, 85, 195, 17, 51, 85, 187, 61, 183, 217, 495, 5, 15, 25, 55, 25, 75, 85, 195, 25, 75, 125, 275, 85, 255, 305, 695, 17, 51, 85, 187, 85, 255, 289, 663
OFFSET
0,3
COMMENTS
In the original toothpick sequence A139250, a toothpick simply turned ON (and stayed ON) if its midpoint was adjacent to exactly one ON toothpick.
Related to A139250 in the same way that A079315 is related to A147562.
LINKS
David Applegate, Omar E. Pol and N. J. A. Sloane, The Toothpick Sequence and Other Sequences from Cellular Automata, Congressus Numerantium, Vol. 206 (2010), 157-191. [There is a typo in Theorem 6: (13) should read u(n) = 4.3^(wt(n-1)-1) for n >= 2.]
FORMULA
a(n) = a(n-1) + A151888(n).
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Jul 23 2009
EXTENSIONS
Terms after a(8) from Nathaniel Johnston, Apr 02 2011
STATUS
approved