6,1

If the first appearance of n in A003005 is A003005(k) = n, then a(n) = k-1. - Fausto A. C. Cariboni, Jun 17 2018

Fausto A. C. Cariboni, Table of n, a(n) for n = 6..95

B. E. Brown and D. M. Gordon, On sequences without geometric progressions, Math. Comp. 65 (1996), no. 216, 1749-1754.

Sean A. Irvine, Example sets for a(6)-a(38)

Cf. A005047, A005048, A005049.

Sequence in context: A108613 A081408 A143616 * A120191 A059983 A177106

Adjacent sequences: A005047 A005048 A005049 * A005051 A005052 A005053

nonn

N. J. A. Sloane

More terms from David W. Wilson, May 15 1997

a(25)-a(38) from Sean A. Irvine, Mar 17 2016

a(39)-a(71) from Fausto A. C. Cariboni, Jun 17 2018

approved