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A161833
First differences of A161832.
3
1, 1, 2, 1, 2, 2, 4, 2, 2, 2, 4, 3, 4, 5, 9, 5, 2
OFFSET
1,3
COMMENTS
Number of Y-toothpicks added to the sieve at the n-th round.
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) = A161831(n+1)/2.
CROSSREFS
KEYWORD
more,nonn
AUTHOR
Omar E. Pol, Jun 20 2009
STATUS
approved