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A008882 3x+1 sequence starting at 99. 2
99, 298, 149, 448, 224, 112, 56, 28, 14, 7, 22, 11, 34, 17, 52, 26, 13, 40, 20, 10, 5, 16, 8, 4, 2, 1, 4, 2, 1, 4, 2, 1, 4, 2, 1, 4, 2, 1, 4, 2, 1, 4, 2, 1, 4, 2, 1, 4, 2, 1, 4, 2, 1, 4, 2, 1, 4, 2, 1, 4, 2, 1, 4, 2, 1, 4, 2, 1, 4 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

REFERENCES

R. K. Guy, Unsolved Problems in Number Theory, E16.

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 0..200

Index entries for sequences related to 3x+1 (or Collatz) problem

Index entries for linear recurrences with constant coefficients, signature (0, 0, 1).

MAPLE

f := proc(n) option remember; if n = 0 then 99; elif f(n-1) mod 2 = 0 then f(n-1)/2 else 3*f(n-1)+1; fi; end;

MATHEMATICA

NestList[If[EvenQ[#], #/2, 3#+1]&, 99, 70] (* Harvey P. Dale, Jul 28 2014 *)

PROG

(MAGMA) [n eq 1 select 99 else IsOdd(Self(n-1)) select 3*Self(n-1)+1 else Self(n-1) div 2: n in [1..80]]; // Vincenzo Librandi, Jul 29 2014

(PARI) Collatz(n, lim=0)={

my(c=n, e=0, L=List(n)); if(lim==0, e=1; lim=n*10^6);

for(i=1, lim, if(c%2==0, c=c/2, c=3*c+1); listput(L, c); if(e&&c==1, break));

return(Vec(L)); }

print(Collatz(99, 60)) \\ A008882 (from 99 first 60)

\\ Anatoly E. Voevudko, Mar 26 2016

CROSSREFS

Sequence in context: A259995 A125820 A008902 * A156757 A027579 A304675

Adjacent sequences:  A008879 A008880 A008881 * A008883 A008884 A008885

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane.

STATUS

approved

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Last modified July 23 15:58 EDT 2019. Contains 325258 sequences. (Running on oeis4.)