A151668 G.f.: Product_{k>=0} (1 + 2*x^(3^k)).

1, 2, 0, 2, 4, 0, 0, 0, 0, 2, 4, 0, 4, 8, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 4, 0, 4, 8, 0, 0, 0, 0, 4, 8, 0, 8, 16, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 4, 0, 4, 8, 0, 0, 0, 0, 4, 8, 0, 8, 16, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0

Offset

0,2

Links

Table of n, a(n) for n=0..104.

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

Crossrefs

For generating functions Product_{k>=0} (1 + a*x^(b^k)) for the following values of (a,b) see: (1,2) A000012 and A000027, (1,3) A039966 and A005836, (1,4) A151666 and A000695, (1,5) A151667 and A033042, (2,2) A001316, (2,3) A151668, (2,4) A151669, (2,5) A151670, (3,2) A048883, (3,3) A117940, (3,4) A151665, (3,5) A151671, (4,2) A102376, (4,3) A151672, (4,4) A151673, (4,5) A151674.

Sequence in context: A089839 A206823 A335407 * A086151 A099040 A185296

Adjacent sequences: A151665 A151666 A151667 * A151669 A151670 A151671

Keyword

nonn

Author

N. J. A. Sloane, May 30 2009

Status

approved