OFFSET
0,3
LINKS
Shawn A. Broyles, 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.]
T. Pisanski and T. W. Tucker, Growth in Repeated Truncations of Maps, Preprint series, Univ. of Ljubljana, Vol. 38 (2000), 696.
N. J. A. Sloane, Catalog of Toothpick and Cellular Automata Sequences in the OEIS
MATHEMATICA
f[n_] := f[n] = Sum[ Binomial[1, n - k]Mod[ Binomial[k, j], 2], {k, 0, n}, {j, 0, k}]; g[n_] := Sum[ f@k, {k, 0, n}]; Array[g, 55, 0] (* Robert G. Wilson v, Jun 28 2010 *)
PROG
(PARI) f(n) = sum(k=0, n, binomial(1, n-k)*sum(j=0, k, binomial(k, j) % 2));
a(n) = if (n==0, 0, sum(k=0, n-1, f(k))); \\ or
lista(nn) = {print1(s=0, ", "); for (n=0, nn-1, s += f(n); print1(s, ", "); ); } \\ Michel Marcus, Apr 29 2018
CROSSREFS
KEYWORD
nonn
AUTHOR
Omar E. Pol, May 29 2010
EXTENSIONS
More terms from Robert G. Wilson v, Jun 28 2010
STATUS
approved