Big numbers, programming contest

Ed Pegg Jr edp at wolfram.com
Mon Jul 4 19:14:25 CEST 2005


For http://www.mathpuzzle.com/ recently, I ran a puzzle based on
sequence A023199 -- a(n) = least k with sigma(k) >= nk

http://www.research.att.com/projects/OEIS?Anum=A023199

The numbers there get large quickly, unless they are represented
differently.  Then, they are quite managable.  I'm not sure what
the ninth term is.  The sequence 3 5 11 17 29 53 89 157 XX 487
seems interesting as well.

{3!, 5!, 11#3!2, 17#5!2, 29#7!4, 53#7!12, 89#11!2,
157#17#8!6, ???, 487#*29#*10!/2}

Perhaps the sequence, in this form, could be extended in the comments.

NJA and the Seq Fan list helped with defining some interesting
problem sets.  Now, the Al Zimmermann programming contests have
returned.  http://www.recmath.org/contest/  Not as sequency as
the upcoming challenges.  Feel free to suggest any new challenges
to the discussion board at the site.







More information about the SeqFan mailing list