A123481 Record n for the sequence A006666(n)/log(n), for n > 1; i.e., the n at which the number of steps to 1 for the halving-Collatz iteration divided by log(n) sets a new maximum.

2, 3, 7, 9, 27, 230631, 626331, 837799, 1723519, 3732423, 6649279, 8400511, 63728127, 3743559068799, 100759293214567, 104899295810901231

Offset: 1

Author

Diego Dominici (dominicd(AT)newpaltz.edu), Apr 16 2007

Keywords

• nonn

Comments

These numbers (for n > 2, at least) are called "Abby-Normal" numbers by Dominici in the referenced paper (definition 21); 2 is included here to agree with the RECORDS transform convention. - D. S. McNeil, Mar 26 2009

Three further terms are known (see Roosendaal) but they may not be the next three terms. - N. J. A. Sloane, Oct 21 2012

Links

• D. Dominici, Working with 2s and 3s, arXiv:0704.1057
• Eric Roosendaal, 3x+1 Completeness and Gamma Records - From _N. J. A. Sloane_, Oct 21 2012

Extensions

Definition edited by D. S. McNeil, Mar 26 2009

Extended by D. S. McNeil, Mar 26 2009

a(13) from Donovan Johnson, Feb 16 2011

a(14)-a(16) from Roosendaal's table added by N. J. A. Sloane, Oct 21 2012