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 A279406 Irregular triangle read by rows: T(n,k) (n>=1, 0 <= k <= n^2) = minimal number of squares attacked by k queens on an n X n toroidal board. 2
 0, 1, 0, 4, 4, 4, 4, 0, 9, 9, 9, 9, 9, 9, 9, 9, 9, 0, 12, 14, 15, 15, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 0, 17, 22, 23, 24, 24, 24, 24, 24, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 0, 20, 26, 30, 30, 32, 32, 34, 34, 34 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,4 COMMENTS A279405(n) is maximal m such that T(n,m) >= m. Generally, T(n,k') <= n^2-k if and only if T(n,k) <= n^2-k'. LINKS Table of n, a(n) for n=1..70. Andrey Zabolotskiy, First 9 rows of the triangle and a part of row 10 FORMULA T(n,0) = 0. T(n,k) = A000290(n) for k > A000290(n) - T(n,1). T(n,1) = A047461(n) = A000290(n) - A279403(n,1). EXAMPLE The triangle begins: 0 1 0 4 4 4 4 0 9 9 9 9 9 9 9 9 9 0 12 14 15 15 16 16 16 16 16 16 16 16 16 16 16 16 CROSSREFS Cf. A000290, A250000, A274947, A274948, A279405, A279403. Sequence in context: A268368 A274947 A331961 * A171408 A071907 A172369 Adjacent sequences: A279403 A279404 A279405 * A279407 A279408 A279409 KEYWORD nonn,tabf AUTHOR Andrey Zabolotskiy, Dec 11 2016 STATUS approved

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Last modified November 28 09:18 EST 2023. Contains 367412 sequences. (Running on oeis4.)