A344719 Minimum number of cells in an n X n grid that need to be painted so that each unpainted cell is orthogonally adjacent to exactly two painted cells.

1, 2, 5, 8, 11, 17, 21, 28, 35, 42, 51, 60, 69, 80, 91

Offset

1,2

Links

Table of n, a(n) for n=1..15.

Dmitry Kamenetsky, Example solutions for n <= 11.

Puzzling StackExchange, Paint Eleven Squares, 2021.

Crossrefs

Cf. A344301.

Sequence in context: A300272 A352143 A365808 * A192147 A226817 A154484

Adjacent sequences: A344716 A344717 A344718 * A344720 A344721 A344722

Keyword

nonn,hard,more

Author

Dmitry Kamenetsky, May 28 2021

Extensions

a(12)-a(15) from Bert Dobbelaere, Jun 13 2021

Status

approved