A005050 Minimal span of set of n elements with no 6-term arithmetic progression.

6, 7, 8, 9, 11, 12, 13, 14, 16, 17, 18, 19, 21, 22, 23, 24, 25, 28, 31, 32, 34, 35, 36, 38, 39, 40, 43, 44, 45, 47, 48, 49, 50, 53, 55, 57, 58, 60, 61, 63, 64, 65, 67, 69, 70, 72, 73, 74, 75, 79, 81, 82, 84, 85, 87, 88, 90, 92, 93, 94, 95, 97, 98, 99, 100, 104

Offset

6,1

Comments

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

Links

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)

Crossrefs

Cf. A005047, A005048, A005049.

Sequence in context: A108613 A081408 A143616 * A309265 A309404 A120191

Adjacent sequences: A005047 A005048 A005049 * A005051 A005052 A005053

Keyword

nonn

Author

N. J. A. Sloane

Extensions

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

Status

approved