A212444 Iterates A212439, starting from 0.

0, 1, 3, 6, 13, 27, 54, 108, 216, 433, 867, 1734, 3469, 6939, 13878, 27756, 55512, 111025, 222050, 444101, 888202, 1776404, 3552808, 7105617, 14211235, 28422470, 56844941, 113689883, 227379766, 454759532, 909519064, 1819038129, 3638076259, 7276152518

Offset

0,3

Links

Amiram Eldar, Table of n, a(n) for n = 0..1000 (terms 0..100 from Reinhard Zumkeller)

Benjamin Chaffin, John P. Linderman, N. J. A. Sloane, and Allan R. Wilks, On Curling Numbers of Integer Sequences, Journal of Integer Sequences, Vol. 16 (2013), Article 13.4.3.

Index entries for sequences related to binary expansion of n.

Formula

a(n+1) = A212439(a(n)) = 2*a(n) + A181935(a(n)) mod 2, a(0) = 0.

2*a(n) <= a(n+1) <= 2*a(n) + 1.

Mathematica

f[n_, e_] := Module[{d = IntegerDigits[n, 2^e]}, Length[Split[d][[-1]]] - If[SameQ @@ d && Mod[n, 2^e] < 2^(e - 1), 1, 0]]; s[n_] := 2*n + Mod[Max[Table[f[n, e], {e, Range[Max[1, Floor[Log2[n]]]]}]], 2]; s[0] = 1; NestList[s, 0, 33] (* Amiram Eldar, Apr 08 2025 *)

Prog

(Haskell)
a212444 n = a212444_list !! n
a212444_list = iterate a212439 0

Crossrefs

Cf. A181935, A212439.

Sequence in context: A281100 A276129 A123247 * A112306 A291753 A033129

Adjacent sequences: A212441 A212442 A212443 * A212445 A212446 A212447

Keyword

nonn,base

Author

Reinhard Zumkeller, May 17 2012

Status

approved