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A337501 Minimum number of painted cells in an n X n grid to avoid unpainted trominoes. 3
0, 2, 4, 8, 11, 18, 23, 32, 39, 50 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..10.

EXAMPLE

For n = 3, painting only 3 cells would leave an unpainted tromino, but painting the following 4 cells avoids all unpainted trominoes:

. . X

X X .

. . X

CROSSREFS

Sequence in context: A120632 A007295 A053439 * A180379 A033956 A282620

Adjacent sequences:  A337498 A337499 A337500 * A337502 A337503 A337504

KEYWORD

nonn,more

AUTHOR

Rob Pratt, Aug 29 2020

STATUS

approved

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Last modified February 27 05:37 EST 2021. Contains 341649 sequences. (Running on oeis4.)