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A121386 Number of different two-colorings of {1,...,n} that minimize the number of monochromatic three-term arithmetic progressions that such a coloring can contain. 1
2, 4, 6, 10, 14, 20, 16, 6, 36, 8, 44, 10, 8, 30, 16, 8, 12, 2, 12, 28, 64, 110, 96, 134, 56, 44, 16, 2, 16, 74, 116, 188, 200, 180 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

The unique (up to switching colors) sequences for n=18 and n=28 are 001001111000011011 and 0001100011111100000011100111 respectively.

LINKS

Table of n, a(n) for n=1..34.

EXAMPLE

a(3)=6 because all non-monochromatic colorings are such an example

CROSSREFS

Cf. A005346, A121385.

Sequence in context: A036641 A260732 A062425 * A007777 A082379 A167379

Adjacent sequences:  A121383 A121384 A121385 * A121387 A121388 A121389

KEYWORD

nonn

AUTHOR

Steve Butler, Jul 26 2006

EXTENSIONS

Definition corrected by Rob Pratt, Jun 11 2014

STATUS

approved

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Last modified September 28 05:33 EDT 2020. Contains 337392 sequences. (Running on oeis4.)