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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A217921 Number of steps to calculate A175872(n). 2
0, 1, 0, 2, 1, 2, 0, 2, 2, 1, 3, 3, 3, 2, 0, 2, 2, 4, 3, 3, 1, 4, 3, 2, 3, 3, 2, 2, 3, 2, 0, 2, 2, 4, 2, 2, 4, 3, 2, 3, 4, 1, 3, 4, 3, 4, 3, 2, 2, 4, 3, 3, 3, 2, 2, 3, 2, 3, 2, 2, 3, 2, 0, 2, 2, 4, 2, 2, 4, 2, 3, 2, 2, 4, 5, 3, 4, 2, 2, 3, 4, 3, 3, 3, 1, 4 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,4

COMMENTS

a(A000225(n)) = 0; a(A000975(n)) = 1.

LINKS

Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

EXAMPLE

n=100, 4 steps: [1,1,0,0,1,0,0]->[2,2,1,2]->[2,1,1]->[1,2]->[1,1], therefore a(100)=4, A175872(100)=2;

n=127, no step: [1,1,1,1,1,1,1], therefore a(127)=0, A175872(127)=7;

n=128, 2 steps: [1,0,0,0,0,0,0,0]->[1,7]->[1,1], therefore a(128)=2, A175872(128)=2;

n=129, 2 steps: [1,0,0,0,0,0,0,1]->[1,6,1]->[1,1,1], therefore a(129)=2, A175872(129)=3;

n=130, 4 steps: [1,0,0,0,0,0,1,0]->[1,5,1,1]->[1,1,2]->[2,1]->[1,2], therefore a(130)=4, A175872(130)=2;

n=131, 2 steps: [1,0,0,0,0,0,1,1]->[1,5,2]->[1,1,1], therefore a(131)=2, A175872(100)=3.

PROG

(Haskell)

import Data.List (group, genericLength)

a217921 n = fst $ until (all (== 1) . snd) f (0, a030308_row n) where

   f (i, xs)  = (i + 1, map genericLength $ group xs)

CROSSREFS

Cf. A030308.

Sequence in context: A118207 A327274 A055378 * A272328 A334956 A335881

Adjacent sequences:  A217918 A217919 A217920 * A217922 A217923 A217924

KEYWORD

nonn

AUTHOR

Reinhard Zumkeller, Mar 26 2013

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.

License Agreements, Terms of Use, Privacy Policy. .

Last modified March 2 19:18 EST 2021. Contains 341756 sequences. (Running on oeis4.)