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A170856 a(0) = 0, a(1) = 1; a(2^i + j) = 2a(j) + 3a(j + 1) for 0 <= j < 2^i. 1
0, 1, 3, 11, 3, 11, 39, 31, 3, 11, 39, 31, 39, 139, 171, 71, 3, 11, 39, 31, 39, 139, 171, 71, 39, 139, 171, 179, 495, 791, 555, 151, 3, 11, 39, 31, 39, 139, 171, 71, 39, 139, 171, 179, 495, 791, 555, 151, 39, 139, 171, 179, 495, 791, 555, 259, 495, 791, 879, 1843, 3363, 3247 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

Robert Israel, Table of n, a(n) for n = 0..10000

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.]

N. J. A. Sloane, Catalog of Toothpick and Cellular Automata Sequences in the OEIS

MAPLE

f:= proc(n) option remember; local j;

   j:= n - 2^ilog2(n);

   2*procname(j)+3*procname(j+1);

end proc:

f(0):= 0: f(1):= 1:

map(f, [$0..100]); # Robert Israel, Jun 12 2018

CROSSREFS

Sequence in context: A244237 A238683 A303114 * A176781 A306367 A226625

Adjacent sequences:  A170853 A170854 A170855 * A170857 A170858 A170859

KEYWORD

nonn,look

AUTHOR

N. J. A. Sloane, Jan 02 2010

STATUS

approved

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Last modified December 15 20:00 EST 2019. Contains 330000 sequences. (Running on oeis4.)