A008875 3x+1 sequence starting at 95.

95, 286, 143, 430, 215, 646, 323, 970, 485, 1456, 728, 364, 182, 91, 274, 137, 412, 206, 103, 310, 155, 466, 233, 700, 350, 175, 526, 263, 790, 395, 1186, 593, 1780, 890, 445, 1336, 668, 334, 167, 502, 251, 754, 377, 1132, 566, 283, 850, 425, 1276, 638, 319, 958, 479, 1438, 719, 2158, 1079, 3238

Offset: 0

Author

N. J. A. Sloane

Keywords

• nonn

References

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

Links

• T. D. Noe, Table of n, a(n) for n=0..105
• Index entries for sequences related to 3x+1 (or Collatz) problem

Crossrefs

Cf. A006370, A008874.

Row 95 of A347270.

Programs

Haskell

a008875 n = a008875_list !! n
a008875_list = drop 2 a008874_list
-- Reinhard Zumkeller, Aug 30 2012

Magma

[n eq 1 select 95 else IsOdd(Self(n-1)) select 3*Self(n-1)+1 else Self(n-1) div 2: n in [1..70]]; // Vincenzo Librandi, Jul 29 2014

Maple

f := proc(n) option remember; if n = 0 then 95; 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]&,95,60] (* Harvey P. Dale, Dec 02 2012 *)

Formula

a(n) = A008874(n + 2).

Extensions

More terms from Larry Reeves (larryr(AT)acm.org), Apr 27 2001