OFFSET
1,1
COMMENTS
All Wagstaff primes A000979 are members of this sequence. - Omar E. Pol, Mar 12 2012
LINKS
R. J. Mathar, Table of n, a(n) for n = 1..181
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.], arXiv:1004.3036
Chris K. Caldwell and G. L. Honaker, Jr., Prime Curios! 2011
N. J. A. Sloane, Catalog of Toothpick and Cellular Automata Sequences in the OEIS
EXAMPLE
MATHEMATICA
toothpicks = With[{terms = 200}, CoefficientList[(x/((1-x)(1+2x)))(1 + 2x Product[1 + x^(2^k-1) + 2 x^(2^k), {k, 0, Log[2, terms] // Ceiling}]) + O[x]^terms, x]];
Select[toothpicks, PrimeQ] (* Jean-François Alcover, Aug 05 2018 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Omar E. Pol, Apr 24 2008
EXTENSIONS
More terms from Omar E. Pol, Dec 20 2008
Terms beyond 2731 from R. J. Mathar, Jan 21 2010
STATUS
approved