A178042 Consider the weighted Farey tree A177405/A177407; a(n) = row at which the denominator 2n+1 first appears (assumes first row is labeled row 1).

1, 2, 3, 3, 3, 4, 4, 5, 4, 4, 5, 5, 5, 4, 5, 5, 6, 6, 6, 6, 5, 5, 6, 5, 6, 7, 5, 5, 7, 6, 7, 6, 6, 6, 6, 6, 6, 6, 6, 6, 5, 6, 7, 8, 7, 7, 7, 7, 7, 6, 7, 6, 7, 7, 7, 7, 6, 7, 8, 7, 7, 7, 7, 7, 7, 7, 6, 7, 6, 8, 8, 7, 7, 8, 8, 7, 8, 7, 7, 7, 6, 6, 8, 7, 7, 7, 8, 8, 8, 7, 7, 7, 8, 8, 7, 8, 8, 8, 7, 8, 8

Offset: 0

Author

N. J. A. Sloane, Dec 16 2010

Keywords

• nonn

Comments

Equals A177903 + 1. See that entry for further information.