The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A133162 Trajectory of 1 under the morphism 1 -> {1,1,2,1}, 2 -> {2}. 4
 1, 1, 2, 1, 1, 1, 2, 1, 2, 1, 1, 2, 1, 1, 1, 2, 1, 1, 1, 2, 1, 2, 1, 1, 2, 1, 2, 1, 1, 2, 1, 1, 1, 2, 1, 2, 1, 1, 2, 1, 1, 1, 2, 1, 1, 1, 2, 1, 2, 1, 1, 2, 1, 1, 1, 2, 1, 1, 1, 2, 1, 2, 1, 1, 2, 1, 2, 1, 1, 2, 1, 1, 1, 2, 1, 2, 1, 1, 2, 1, 2, 1, 1, 2, 1, 1, 1, 2, 1, 2, 1, 1, 2, 1, 1, 1, 2, 1, 1 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 COMMENTS It can be shown that this is lim_{t -> oo} S_t, where S_0 = 1, S_{t+1} = S_t S_t 2 S_t. Suggested by A131989: a(n) = length of n-th run of 1's in A131989. For a proof of this see the Comments of A131989. - Michel Dekking, Oct 19 2019 LINKS Seiichi Manyama, Table of n, a(n) for n = 1..10000 FORMULA Denote the sequence by a(1), a(2), ... Block t, that is, S_t, extends from n=1 through n=(3^(t+1)-1)/2. Given n, to find a(n): first find t from p = (3^t-1)/2 < n <= (3^(t+1)-1)/2. Then if n=3^t, a(n) = 2. Otherwise, a(n) = a(n'), where n' = n-p if n<3^t, otherwise n' = n-2p-1. EXAMPLE Nest[Function[l, {Flatten[(l /. {1 -> {1,1,2,1}, 2 -> {2} })] }], {1}, 5] (* Georg Fischer, Jul 19 2019 *) CROSSREFS Cf. A049320, A131989, A317962. Sequence in context: A184303 A218545 A205600 * A276172 A322028 A079806 Adjacent sequences:  A133159 A133160 A133161 * A133163 A133164 A133165 KEYWORD nonn,easy AUTHOR N. J. A. Sloane, Oct 09 2007, Oct 10 2007 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified September 29 18:27 EDT 2020. Contains 337432 sequences. (Running on oeis4.)