login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A308881 Irregular array read by rows: row k (k>=1) contains k^2 numbers, formed by filling in a k X k square by upwards antidiagonals so entries in all rows, columns, diagonals, antidiagonals are distinct, and then reading that square across rows. 2
0, 0, 2, 1, 3, 0, 2, 1, 1, 3, 4, 2, 0, 5, 0, 2, 1, 5, 1, 3, 4, 0, 2, 0, 5, 1, 3, 1, 2, 4, 0, 2, 1, 5, 3, 1, 3, 4, 0, 6, 2, 0, 5, 1, 7, 3, 1, 2, 4, 0, 4, 5, 0, 3, 1, 0, 2, 1, 5, 3, 4, 1, 3, 4, 0, 7, 2, 2, 0, 5, 1, 6, 9, 3, 1, 2, 4, 0, 5, 4, 6, 0, 3, 1, 7, 5, 7, 8, 6, 4, 10 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

The first row of the k X k square converges to A295563 as k increases.

When filling in the k X k square, always choose the smallest possible number. Each k X k square is uniquely determined.

LINKS

I. V. Serov, Rows of first 32 squares, flattened (There are 1^2+2^2+...+32^2 = 11440 entries.)

F. Michel Dekking, Jeffrey Shallit, and N. J. A. Sloane, Queens in exile: non-attacking queens on infinite chess boards, arXiv:1907.09120, July 2019

EXAMPLE

The first eight squares are (here A=10, B=11, C=12):

0

--------

02

13

--------

021

134

205

--------

0215

1340

2051

3124

--------

02153

13406

20517

31240

45031

--------

021534

134072

205169

312405

460317

57864A

--------

0215349

1340725

2051864

3124058

4603172

5786493

6432587

--------

0215349A

13407258

20518643

31240786

4603152B

5786493C

64325879

756893A2

--------

CROSSREFS

Cf. A295563, A308880.

Sequence in context: A071467 A125073 A325310 * A281488 A071461 A091829

Adjacent sequences:  A308877 A308878 A308880 * A308882 A308883 A308884

KEYWORD

nonn,tabf

AUTHOR

N. J. A. Sloane, Jun 29 2019

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified February 21 04:55 EST 2020. Contains 332086 sequences. (Running on oeis4.)