

A271479


Number of steps for the trajectory of n under the map k > A271478(k) to reach 1.


3



0, 1, 4, 2, 7, 5, 5, 3, 10, 8, 8, 6, 8, 6, 6, 4, 13, 11, 11, 9, 11, 9, 9, 7, 11, 9, 9, 7, 9, 7, 7, 5, 16, 14, 14, 12, 14, 12, 12, 10, 14, 12, 12, 10, 12, 10, 10, 8, 14, 12, 12, 10, 12, 10, 10, 8, 12, 10, 10, 8, 10, 8, 8, 6, 19, 17, 17, 15, 17, 15, 15, 13, 17, 15, 15, 13, 15, 13
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OFFSET

1,3


COMMENTS

Arises in studying A266569.
Records are 0, 1, 4, 7, 10, 13, 16, 19, 22, 25, 28, 31, 34, 37, 40, ... and occur at positions 1, 2, 3, 5, 9, 17, 33, 65, 129, 257, 513, 1025, 2049, 4097, 8193, ...


LINKS

N. J. A. Sloane, Table of n, a(n) for n = 1..10000


FORMULA

It appears that a(1) = 0, a(n) = 1 + 2*(n mod 2) + a(ceiling(n/2)) for n > 1.  Christian Krause, Apr 28 2019


MAPLE

f:=n>if n mod 2 = 0 then n/2 else 2*n+2; fi; # A271478
a:=[]; B:=1000;
for n from 1 to 100 do
ct:=0; s:=n;
for k from 1 to B while s>1 do
s:=f(s); ct:=ct+1; od:
if ct=B then lprint("error, need to increase limit B"); break; fi;
a:=[op(a), ct]; od:
a;


MATHEMATICA

Table[Length[NestWhileList[If[EvenQ[#], #/2, 2#+2]&, n, #!=1&]]1, {n, 80}] (* Harvey P. Dale, May 02 2017 *)


CROSSREFS

Cf. A266569, A271478.
Sequence in context: A115302 A109857 A194075 * A259927 A002560 A124908
Adjacent sequences: A271476 A271477 A271478 * A271480 A271481 A271482


KEYWORD

nonn


AUTHOR

N. J. A. Sloane, Apr 10 2016


STATUS

approved



