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A320040 Consider the Cantor matrix of rational numbers. This sequence reads the numerator, then the denominator as one moves through the matrix along alternate up and down antidiagonals.

Original entry on oeis.org

1, 1, 1, 2, 2, 1, 3, 1, 2, 2, 1, 3, 1, 4, 2, 3, 3, 2, 4, 1, 5, 1, 4, 2, 3, 3, 2, 4, 1, 5, 1, 6, 2, 5, 3, 4, 4, 3, 5, 2, 6, 1, 7, 1, 6, 2, 5, 3, 4, 4, 3, 5, 2, 6, 1, 7, 1, 8, 2, 7, 3, 6, 4, 5, 5, 4, 6, 3, 7, 2, 8, 1, 9, 1, 8, 2, 7, 3, 6, 4, 5, 5, 4, 6, 3, 7, 2, 8, 1, 9
Offset: 1

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Author

Robert G. Wilson v, Oct 03 2018

Keywords

Comments

This is analogous to reading the rows of a triangle in boustrophedon order.
The antidiagonals are in a certain sense palindromic.

Examples

			The Cantor Matrix begins:
=========================================================================
n\d|   1    2    3    4    5    6    7    8    9    10    11    12    13
---|---------------------------------------------------------------------
1  |  1/1  1/2  1/3  1/4  1/5  1/6  1/7  1/8  1/9  1/10  1/11  1/12  1/13
2  |  2/1  2/2  2/3  2/4  2/5  2/6  2/7  2/8  2/9  2/10  2/11  2/12  2/13
3  |  3/1  3/2  3/3  3/4  3/5  3/6  3/7  3/8  3/9  3/10  3/11  3/12  3/13
4  |  4/1  4/2  4/3  4/4  4/5  4/6  4/7  4/8  4/9  4/10  4/11  4/12  4/13
5  |  5/1  5/2  5/3  5/4  5/5  5/6  5/7  5/8  5/9  5/10  5/11  5/12  5/13
6  |  6/1  6/2  6/3  6/4  6/5  6/6  6/7  6/8  6/9  6/10  6/11  6/12  6/13
7  |  7/1  7/2  7/3  7/4  7/5  7/6  7/7  7/8  7/9  7/10  7/11  7/12  7/13
8  |  8/1  8/2  8/3  8/4  8/5  8/6  8/7  8/8  8/9  8/10  8/11  8/12  8/13
9  |  9/1  9/2  9/3  9/4  9/5  9/6  9/7  9/8  9/9  9/10  9/11  9/12  9/13
10 | 10/1 10/2 10/3 10/4 10/5 10/6 10/7 10/8 10/9 10/10 10/11 10/12 10/13
11 | 11/1 11/2 11/3 11/4 11/5 11/6 11/7 11/8 11/9 11/10 11/11 11/12 11/13
12 | 12/1 12/2 12/3 12/4 12/5 12/6 12/7 12/8 12/9 12/10 12/11 12/12 12/13
13 | 13/1 13/2 13/3 13/4 13/5 13/6 13/7 13/8 13/9 13/10 13/11 13/12 13/13
...
		

Crossrefs

Programs

  • Mathematica
    (* to read the Cantor Matrix *) Table[{n, d}, {n, 13}, {d, 13}] // Grid