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!)
A253720 a(n) = length of row n in A253676 and A254068, assuming the 3x+1 (or Collatz) conjecture. 2
1, 2, 5, 3, 4, 2, 6, 5, 7, 5, 18, 5, 6, 3, 8, 4, 7, 4, 19, 6, 5, 2, 7, 4, 20, 6, 8, 19, 3, 5, 16, 18, 21, 7, 15, 4, 20, 5, 9, 8, 17, 18, 10, 8, 8, 5, 10, 18, 21, 6, 3, 7, 9, 3, 5, 19, 11, 8, 14, 8, 6, 4, 10, 17, 22, 7 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..66.

FORMULA

For n>1, k>=1, a(n) = a((8+(3*n-2)*4^k)/12).

MATHEMATICA

(* Row lengths of A253676 and A254068: *)

v[n_] := IntegerExponent[n, 2]; f[x_] := (3*x + 1)/2^v[3*x + 1]; s[x_] := (3 + (3/2)^v[1 + f[x]]*(1 + f[x]))/6; A253676[n_] := NestWhileList[s[4*# - 3] &, n, # > 1 &]; Table[Length[A253676[n]], {n, 1, 66}]

CROSSREFS

Cf. A253676, A254068.

Sequence in context: A073480 A077057 A030660 * A309735 A275726 A146096

Adjacent sequences:  A253717 A253718 A253719 * A253721 A253722 A253723

KEYWORD

nonn

AUTHOR

L. Edson Jeffery, May 02 2015

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 May 17 09:03 EDT 2021. Contains 343969 sequences. (Running on oeis4.)