A170861 - OEIS

A170861

a(0) = 1, a(1) = 0; a(2^i + j) = 2a(j) + 3a(j + 1) for 0 <= j < 2^i.

1, 0, 2, 6, 2, 6, 22, 18, 2, 6, 22, 18, 22, 78, 98, 42, 2, 6, 22, 18, 22, 78, 98, 42, 22, 78, 98, 102, 278, 450, 322, 90, 2, 6, 22, 18, 22, 78, 98, 42, 22, 78, 98, 102, 278, 450, 322, 90, 22, 78, 98, 102, 278, 450, 322, 150, 278, 450, 502, 1038, 1906, 1866, 914, 186, 2, 6, 22, 18

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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

A[0]:= 1:A[1]:= 0:

for d from 1 to 7 do

for j from 0 to 2^d-1 do

A[2^d+j]:= 2*A[j]+3*A[j+1]

od od:

seq(A[i], i=0..2^8-1); # Robert Israel, Mar 22 2017

CROSSREFS

Sequence in context: A340857 A241040 A151705 * A229578 A078992 A062321

Adjacent sequences: A170858 A170859 A170860 * A170862 A170863 A170864

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, Jan 02 2010

STATUS

approved