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 A170863 a(0) = 1, a(1) = 1; a(2^i + j) = 3a(j) + a(j + 1) for 0 <= j < 2^i. 1
 1, 1, 4, 7, 4, 7, 19, 25, 4, 7, 19, 25, 19, 40, 82, 79, 4, 7, 19, 25, 19, 40, 82, 79, 19, 40, 82, 94, 97, 202, 325, 241, 4, 7, 19, 25, 19, 40, 82, 79, 19, 40, 82, 94, 97, 202, 325, 241, 19, 40, 82, 94, 97, 202, 325, 256, 97, 202, 340, 379, 493, 931, 1216, 727, 4, 7, 19, 25, 19, 40 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 LINKS Robert Israel, 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.] N. J. A. Sloane, Catalog of Toothpick and Cellular Automata Sequences in the OEIS MAPLE f:= proc(n) option remember; local j; j:= n - 2^ilog2(n); 3*procname(j) + procname(j+1) end proc: f(0):= 1: f(1):= 1: map(f, [\$0..100]); # Robert Israel, Jul 10 2020 MATHEMATICA f[n_] := f[n] = With[{j = n - 2^Floor@Log[2, n]}, 3 f[j] + f[j+1]]; f[0] = f[1] = 1; f /@ Range[0, 100] (* Jean-François Alcover, Aug 31 2020, after Robert Israel *) CROSSREFS Sequence in context: A081884 A059143 A094765 * A021682 A242187 A094692 Adjacent sequences: A170860 A170861 A170862 * A170864 A170865 A170866 KEYWORD nonn,look AUTHOR N. J. A. Sloane, Jan 02 2010 STATUS approved

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Last modified November 29 07:03 EST 2023. Contains 367429 sequences. (Running on oeis4.)