A008883 3x+1 sequence starting at 51.

51, 154, 77, 232, 116, 58, 29, 88, 44, 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, 2, 1

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 51; 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]&, 51, 100] (* Vincenzo Librandi, Jul 29 2014 *)

Prog

(Magma) [n eq 1 select 51 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(51, 60)) \\ A008883 (from 51 first 60)
\\ Anatoly E. Voevudko, Mar 26 2016

Crossrefs

Cf. similar sequences listed in A245671.

Row 51 of A347270.

Sequence in context: A044764 A257352 A353599 * A327624 A069762 A245829

Adjacent sequences: A008880 A008881 A008882 * A008884 A008885 A008886

Keyword

nonn,easy

Author

N. J. A. Sloane.

Status

approved