A278564 Irregular triangle read by rows: row n lists (negated) determinants of the quadratic Farey series of order n.

1, 1, 3, 1, 1, 2, 3, 2, 1, 1, 2, 3, 1, 5, 1, 3, 2, 1, 1, 2, 2, 3, 2, 5, 2, 3, 2, 2, 1, 1, 2, 2, 3, 1, 4, 2, 1, 7, 1, 2, 4, 1, 3, 2, 2, 1, 1, 2, 2, 2, 3, 1, 5, 1, 2, 1, 7, 1, 2, 1, 5, 1, 3, 2, 2, 2, 1, 1, 2, 2, 2, 3, 1, 4, 2, 5, 2, 3, 1, 1, 9, 1, 1, 3, 2, 5, 2, 4, 1, 3, 1, 1, 1, 1, 1, 2, 2, 2, 2, 3, 1, 4, 2, 1, 6, 2, 3, 2, 1, 9, 1, 2, 3, 2, 6, 1, 1, 2, 4, 1, 3, 2, 2, 2, 2, 1

Offset

2,3

Links

Table of n, a(n) for n=2..127.

H. Brown, K. Mahler, A generalization of Farey sequences: Some exploration via the computer, Journal of Number Theory 3.3 (1971): 364-370.

Example

Triangle begins:
1,
1,3,1,
1,2,3,2,1,
1,2,3,1,5,1,3,2,1,
1,2,2,3,2,5,2,3,2,2,1,
1,2,2,3,1,4,2,1,7,1,2,4,1,3,2,2,1,
1,2,2,2,3,1,5,1,2,1,7,1,2,1,5,1,3,2,2,2,1,
1,2,2,2,3,1,4,2,5,2,3,1,1,9,1,1,3,2,5,2,4,1,3,1,1,1,1,
1,2,2,2,2,3,1,4,2,1,6,2,3,2,1,9,1,2,3,2,6,1,1,2,4,1,3,2,2,2,2,1,
...

Crossrefs

Sequence in context: A243925 A348282 A030727 * A269973 A128316 A065836

Adjacent sequences: A278561 A278562 A278563 * A278565 A278566 A278567

Keyword

nonn,tabf

Author

N. J. A. Sloane, Nov 25 2016

Status

approved