A003509 Let k(m) denote the least integer such that every m X m (0,1)-matrix with exactly k(m) ones in each row and in each column contains a 2 X 2 submatrix without zeros. The sequence gives the index n of the first term in each string of equal entries in the {k(m)} sequence (see A155934). (Formerly M0833)

2, 3, 7, 13, 21, 31

Offset

2,1

References

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Links

Table of n, a(n) for n=2..7.

E. T. Wang and R. K. Guy, Problem E2429, Amer. Math. Monthly, 81 (1974), 1112-1113.

Index entries for sequences related to binary matrices

Crossrefs

Cf. A005991 (index of last term), A155934.

Sequence in context: A325875 A049887 A048216 * A238432 A238423 A133370

Adjacent sequences: A003506 A003507 A003508 * A003510 A003511 A003512

Keyword

nonn,more

Author

N. J. A. Sloane

Extensions

Title made more specific by Sean A. Irvine, Jun 04 2015

Status

approved