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 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). 2
 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 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS Equals A177903 + 1. See that entry for further information. LINKS CROSSREFS Sequence in context: A334220 A234016 A029119 * A308950 A193832 A293137 Adjacent sequences:  A178039 A178040 A178041 * A178043 A178044 A178045 KEYWORD nonn AUTHOR N. J. A. Sloane, Dec 16 2010 STATUS approved

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Last modified November 24 17:36 EST 2020. Contains 338616 sequences. (Running on oeis4.)