A170867 a(0) = 1, a(1) = 1; a(2^i + j) = 3a(j) + 3a(j + 1) for 0 <= j < 2^i.

1, 1, 6, 21, 6, 21, 81, 81, 6, 21, 81, 81, 81, 306, 486, 261, 6, 21, 81, 81, 81, 306, 486, 261, 81, 306, 486, 486, 1161, 2376, 2241, 801, 6, 21, 81, 81, 81, 306, 486, 261, 81, 306, 486, 486, 1161, 2376, 2241, 801, 81, 306, 486, 486, 1161, 2376, 2241, 1026, 1161, 2376, 2916

Offset

0,3

Links

Table of n, a(n) for n=0..58.

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

Sequence in context: A338427 A069257 A133885 * A321776 A064929 A298266

Adjacent sequences: A170864 A170865 A170866 * A170868 A170869 A170870

Keyword

nonn

Author

N. J. A. Sloane, Jan 02 2010

Status

approved