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A350281 Square array filled and read by antidiagonals upwards; the first value is 0; if the previous value has already appeared in the table, then the next value is the square of the distance to the nearest earlier position with the same value; otherwise the next value is 0. 1
0, 0, 1, 0, 1, 1, 1, 5, 0, 4, 0, 4, 13, 0, 1, 4, 5, 4, 1, 5, 10, 0, 4, 1, 5, 5, 1, 2, 0, 1, 5, 2, 25, 0, 5, 4, 16, 0, 1, 1, 2, 1, 4, 5, 1, 10, 106, 0, 1, 1, 1, 1, 1, 2, 5, 5, 29, 0, 1, 1, 1, 1, 1, 1, 1, 2, 5, 1, 13, 49, 0, 4, 17, 0, 8, 0, 8, 8, 2, 73, 0, 4, 13, 5, 13, 8, 5, 10, 25, 37, 0 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

0,8

COMMENTS

This sequence is a two-dimensional variant of Van Eck's sequence (A181391).

When working on a square spiral, we quickly end with all 1's:

1--1--1--1--1--1--1

| |

1 1--1--0-13--2 1

. | | |

. 1 1--0--1 0 1

. | | | | |

1 4 0--0 5 1

| | | |

1 0--2--0--1 1

| |

1--1--1--1--1--1

LINKS

Rémy Sigrist, Table of n, a(n) for n = 0..10010

Rémy Sigrist, C++ program

EXAMPLE

Square array begins:

n\k| 0 1 2 3 4 5 6 7 8 9

---+----------------------------------------

0| 0 1 1 4 1 10 2 4 1 5

1| 0 1 0 0 5 1 5 5 2 1

2| 0 5 13 1 5 0 4 1 1 0

3| 1 4 4 5 25 1 1 1 8 10

4| 0 5 1 2 2 1 1 0 5 1

5| 4 4 5 1 1 1 17 8 5 1

6| 0 1 1 1 1 4 13 1 1 29

7| 0 0 0 1 0 5 5 1 25 2

8| 16 106 0 49 13 1 1 2 5 20

9| 10 29 13 4 4 1 8 5 0 2

PROG

(C++) See Links section.

CROSSREFS

Cf. A001481, A181391.

Sequence in context: A258754 A175296 A076266 * A354053 A200102 A016581

Adjacent sequences: A350278 A350279 A350280 * A350282 A350283 A350284

KEYWORD

nonn,tabl

AUTHOR

Rémy Sigrist, Mar 27 2022

STATUS

approved

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Last modified February 7 12:58 EST 2023. Contains 360123 sequences. (Running on oeis4.)