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A098604 Triangle T(n,k) read by rows, for 1 <= k <= n: minimal number of knights needed to cover a k X n board. 3
1, 2, 4, 3, 4, 4, 4, 4, 4, 4, 5, 4, 4, 4, 5, 6, 4, 4, 4, 6, 8, 7, 6, 6, 6, 7, 8, 10, 8, 8, 8, 8, 8, 8, 11, 12, 9, 8, 8, 8, 8, 10, 12, 13, 14, 10, 8, 8, 8, 9, 12, 14, 14, 15, 16, 11, 8, 8, 8, 10, 12, 15, 16, 17, 19, 21, 12, 8, 8, 8, 10, 12, 16, 16, 18, 20, 22, 24, 13, 10, 10, 10, 12, 14 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

How many knights are needed to occupy or attack every square of a k X n board?

I do not know how many of these numbers have been proved to be optimal. - N. J. A. Sloane, Nov 08 2004

LINKS

Table of n, a(n) for n=1..84.

Lee Morgenstern, Knight Domination.

Frank Rubin, Knight coverings for large chessboards, 2000.

Eric Weisstein's World of Mathematics, Knights Problem.

EXAMPLE

Triangle (with rows n >= 1 and columns k >= 1) begins as follows:

  1

  2 4

  3 4 4

  4 4 4 4

  5 4 4 4 5

  6 4 4 4 6 8

  7 6 6 6 7 8 10

  ...

CROSSREFS

See A006075 for the n X n case (the main diagonal). A006076 gives number of ways to cover an n X n board using the minimal number of knights.

Sequence in context: A069655 A004574 A073127 * A274047 A226644 A083172

Adjacent sequences:  A098601 A098602 A098603 * A098605 A098606 A098607

KEYWORD

nonn,tabl,nice

AUTHOR

N. J. A. Sloane

EXTENSIONS

Morgenstern's table extends a long way beyond what is shown here.

STATUS

approved

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Last modified July 15 14:07 EDT 2019. Contains 325030 sequences. (Running on oeis4.)