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A339635 Triangle read by rows, T(n, k) is the least number of 1's in an n X n binary matrix so that every k X k minor contains at least one 1. 0
1, 4, 1, 9, 3, 1, 16, 7, 3, 1, 25, 13, 5, 3, 1 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

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

Chengcheng Yang, A Problem of Erdös Concerning Lattice Cubes, arXiv:2011.15010 [math.CO], 2020. See Table p. 27.

FORMULA

T(n, 1) = n^2; T(n, n) = 1; T(2*n, n) = 3*n+1 = A016777(n).

EXAMPLE

Triangle begins:

   1;

   4,  1;

   9,  3, 1;

  16,  7, 3, 1;

  25, 13, 5, 3, 1;

  ...

CROSSREFS

Cf. A000290, A016777, A152125, A227133.

Sequence in context: A331153 A331149 A331145 * A085691 A055461 A324999

Adjacent sequences:  A339632 A339633 A339634 * A339636 A339637 A339638

KEYWORD

nonn,tabl,more

AUTHOR

Michel Marcus, Dec 11 2020

STATUS

approved

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Last modified May 12 13:46 EDT 2021. Contains 343823 sequences. (Running on oeis4.)