A153004 First differences of toothpick numbers A153003.

1, 3, 3, 3, 6, 9, 6, 3, 6, 9, 9, 12, 21, 24, 12, 3, 6, 9, 9, 12, 21, 24, 15, 12, 21, 27, 30, 45, 66, 60, 24, 3, 6, 9, 9, 12, 21, 24, 15, 12, 21, 27, 30, 45, 66, 60, 27, 12, 21, 27, 30, 45, 66, 63, 42, 45, 69, 84, 105, 156, 192, 144, 48, 3

Offset: 1

Author

Omar E. Pol, Jan 02 2009

Keywords

• nonn

Examples

			Triangle begins:
1;
3,3;
3,6,9,6;
3,6,9,9,12,21,24,12;
3,6,9,9,12,21,24,15,12,21,27,30,45,66,60,24;
		

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

Crossrefs

Cf. A139251, A152968, A152978, A152998, A153000, A153003.

Toothpick sequence: A139250.

Programs

Mathematica

A139250[n_] := A139250[n] = Module[{m, k}, If[n == 0, Return[0]]; m = 2^(Length[IntegerDigits[n, 2]] - 1); k = (2 m^2 + 1)/3; If[n == m, k, k + 2 A139250[n - m] + A139250[n - m + 1] - 1]];
b[n_] := If[n == 0, 0, (3/4) (A139250[n + 1] - 3) + 1];
b /@ Range[0, 64] // Differences (* Jean-François Alcover, Apr 06 2020 *)