A178047 Consider the Farey tree A049455/A049456; a(n) = row at which the denominator n first appears (assumes first row is labeled row 0).

0, 1, 2, 3, 3, 5, 4, 4, 5, 5, 5, 5, 5, 6, 6, 6, 6, 6, 6, 7, 6, 7, 7, 7, 7, 7, 7, 8, 7, 7, 7, 8, 8, 7, 8, 8, 8, 9, 8, 8, 8, 9, 8, 8, 8, 8, 8, 9, 8, 8, 9, 9, 9, 10, 8, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 10, 9, 9, 9, 9, 10, 10, 9, 9, 9, 10, 10, 10, 10, 10, 10, 10, 9, 11, 10, 10, 10, 10, 10, 11

Offset

1,3

Comments

Equals A178031 - 1. See that entry for further information.

Links

Table of n, a(n) for n=1..96.

Richard J. Mathar, The Kepler binary tree of reduced fractions, 2017.

Crossrefs

Cf. A295783 (conjectured frequencies of this).

Sequence in context: A056149 A167494 A091238 * A122954 A268087 A375465

Adjacent sequences: A178044 A178045 A178046 * A178048 A178049 A178050

Keyword

nonn,changed

Author

N. J. A. Sloane, Dec 16 2010

Status

approved