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A170870
a(0) = 1, a(1) = 2; a(2^i + j) = a(j) + 3a(j + 1) for 0 <= j < 2^i.
0
1, 2, 7, 23, 7, 23, 76, 44, 7, 23, 76, 44, 76, 251, 208, 65, 7, 23, 76, 44, 76, 251, 208, 65, 76, 251, 208, 272, 829, 875, 403, 86, 7, 23, 76, 44, 76, 251, 208, 65, 76, 251, 208, 272, 829, 875, 403, 86, 76, 251, 208, 272, 829, 875, 403, 293, 829, 875, 1024, 2759, 3454, 2084
OFFSET
0,2
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.]
CROSSREFS
Sequence in context: A153523 A153551 A125285 * A122631 A269313 A147969
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Jan 02 2010
STATUS
approved