[seqfan] No 3 terms in Geom Progression

Neil Sloane njasloane at gmail.com
Thu Mar 1 18:01:05 CET 2012

*Dear Sequence Fans,*
*A003002 gives the size of the largest subset of [1,2,...,n] which contains
*3-term arithmetic progression.*
*But what is **
he largest subset of [1,2,...,n] which contains no
*3-term geometric progression?*
*E.g. if n=16, it looks like omitting 1 and 4 works, so a(16) = 14*
*A quick hand calculation gives (for n>=1):*
*Could someone correct/extend this?*

Dear Friends, I will soon be retiring from AT&T. New coordinates:

Neil J. A. Sloane, President, OEIS Foundation
11 South Adelaide Avenue, Highland Park, NJ 08904, USA
Phone: 732 828 6098; home page: http://NeilSloane.com
Email: njasloane at gmail.com

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