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A090246 The largest subset of P(Z/3Z)^n that does not contain 3 collinear points. 2
2, 4, 10, 20, 56 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

P(Z/3Z)^n is the projective space of n dimensions over the finite field Z/3Z. This is the size of the largest subset which does not contain 3 points lying in a line.

Davis and Maclagan described a game similar to the game SET that could be played in this space using projective lines, rather than in (Z/3Z)^n using the algebraic notion of line. This sequence is the analog of A090245 for this game.

So far this sequence agrees with A104442.

LINKS

Table of n, a(n) for n=1..5.

B. Davis and D. Maclagan, The Card Game SET, The Mathematical Intelligencer, Vol. 25:3 (Summer 2003), pp. 33-40.

B. L. Davis and D. Maclagan, The Card Game SET [From Omar E. Pol, Feb 21 2009]

Ivars Peterson, SET Math.

Ivars Peterson, SET Math [From Omar E. Pol, Feb 21 2009]

CROSSREFS

Cf. A090245.

Sequence in context: A026395 A247630 A015889 * A104442 A104434 A104433

Adjacent sequences:  A090243 A090244 A090245 * A090247 A090248 A090249

KEYWORD

nonn,more

AUTHOR

Hans Havermann, Jan 23 2004

EXTENSIONS

Edited by Jack W Grahl, May 12 2009

STATUS

approved

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Last modified March 22 04:32 EDT 2019. Contains 321406 sequences. (Running on oeis4.)