OFFSET
0,3
COMMENTS
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.]
N. J. A. Sloane, Catalog of Toothpick and Cellular Automata Sequences in the OEIS.
FORMULA
a(n) = 1 + 4*5^(A000120(n-1)-1), n >= 2. - Nathaniel Johnston, Mar 22 2011
MATHEMATICA
a[n_] := 1 + 4*5^(DigitCount[n-1, 2, 1]-1); a[0] = 0; a[1] = 1; Array[a, 100, 0] (* Amiram Eldar, Aug 01 2023 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Omar E. Pol, Feb 21 2011
EXTENSIONS
More terms from Nathaniel Johnston, Mar 22 2011
More terms from Amiram Eldar, Aug 01 2023
STATUS
approved