A008902 x->x/2 if x even, x->3x-1 if x odd.

99, 296, 148, 74, 37, 110, 55, 164, 82, 41, 122, 61, 182, 91, 272, 136, 68, 34, 17, 50, 25, 74, 37, 110, 55, 164, 82, 41, 122, 61, 182, 91, 272, 136, 68, 34, 17, 50, 25, 74, 37, 110, 55, 164, 82, 41, 122, 61, 182, 91

Offset

0,1

Comments

The definition is similar to the definition of the Collatz (or 3x+1) sequence except that instead of 3x+1 it uses 3x-1. - Harvey P. Dale, Jan 20 2026

References

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

Links

Harvey P. Dale, Table of n, a(n) for n = 0..1000

Index entries for periodic sequences.

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

Mathematica

NestList[If[EvenQ[#], #/2, 3#-1]&, 99, 50] (* Harvey P. Dale, Jan 20 2026 *)

Prog

(PARI) a(n)=if(n>2, 8900968659103151411668874298641981524835525\273^(n%18)%273, [99, 296, 148][n+1]) \\ Charles R Greathouse IV, May 31 2026

Crossrefs

Sequence in context: A250779 A259995 A125820 * A008882 A156757 A027579

Adjacent sequences: A008899 A008900 A008901 * A008903 A008904 A008905

Keyword

nonn,easy

Author

N. J. A. Sloane

Status

approved