A033492 Record number of steps to reach 1 in '3x+1' problem, corresponding to starting values in A006877 (same as A006878 except here we start counting at 1 instead of 0).

1, 2, 8, 9, 17, 20, 21, 24, 112, 113, 116, 119, 122, 125, 128, 131, 144, 145, 171, 179, 182, 183, 209, 217, 238, 262, 268, 276, 279, 282, 308, 311, 324, 340, 351, 354, 375, 383, 386, 443, 449, 470, 509, 525, 528, 531, 557, 560, 563, 584, 597, 613, 665, 686

Offset: 1

Author

Jeff Burch

Keywords

• nonn

Comments

Both the 3x+1 steps and the halving steps are counted.

References

• R. E. Maeder, Programming in Mathematica, 3rd Edition, Addison-Wesley, pages 251-252.

Links

• T. D. Noe, Table of n, a(n) for n=1..130 (from Eric Roosendaal's data)
• Eric Roosendaal, 3x+1 Delay Records
• Index entries for sequences related to 3x+1 (or Collatz) problem

Crossrefs

Equal to A006878 + 1. Cf. A006884, A006885, A033492.

Extensions

Corrected and extended by Lee Corbin (lcorbin(AT)tsoft.com)

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