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Sums of two successive terms of A256249, with a(0) = 0.
4

%I #34 Feb 26 2023 19:42:26

%S 0,1,3,7,11,15,23,35,43,47,55,67,83,103,127,155,171,175,183,195,211,

%T 231,255,283,315,351,391,435,483,535,591,651,683,687,695,707,723,743,

%U 767,795,827,863,903,947,995,1047,1103,1163,1227,1295,1367,1443,1523,1607,1695,1787,1883,1983,2087,2195,2307,2423,2543,2667,2731

%N Sums of two successive terms of A256249, with a(0) = 0.

%C Also bisection of A266540.

%C It appears that this sequence has a fractal-like behavior (see Plot 2, A139250 vs. this sequence).

%C First differs from both the toothpick sequence A139250 and A256265 at a(12), with which it shares infinitely many terms.

%H Michel Marcus, <a href="/A266535/b266535.txt">Table of n, a(n) for n = 0..10000</a>

%H N. J. A. Sloane, <a href="/wiki/Catalog_of_Toothpick_and_CA_Sequences_in_OEIS">Catalog of Toothpick and Cellular Automata Sequences in the OEIS</a>

%H <a href="/index/Ce#cell">Index entries for sequences related to cellular automata</a>

%t Most@ # + Rest@ # &@ Accumulate@ Join[{0, 0}, Flatten@ Table[Range[1, 2^n - 1, 2], {n, 0, 6}]] (* _Michael De Vlieger_, Jan 05 2016, after _Ivan N. Ianakiev_ at A256249 *)

%o (PARI) f(n)=n++; b=#binary(n>>1); (4^b-1)/3+(n-2^b)^2; \\ A256249

%o a(n) = if (n, f(n)+f(n-1), 0);

%Y Cf. A006257, A139250, A256249, A256265, A266539, A266540.

%K nonn

%O 0,3

%A _Omar E. Pol_, Jan 02 2016