A261179 Take the list of positive rationals {R(n): n>=1} in the order defined by Calkin and Wilf (Recounting the Rationals, 1999); a(n) = numerator of R(prime(n)).

1, 2, 3, 3, 5, 5, 5, 7, 7, 7, 5, 11, 11, 13, 9, 13, 11, 9, 11, 13, 15, 13, 19, 17, 11, 19, 17, 21, 19, 13, 7, 13, 19, 23, 29, 25, 23, 25, 27, 31, 29, 31, 13, 13, 25, 23, 31, 17, 23, 27, 25, 19, 17, 17, 9, 19, 27, 21, 37, 31, 35, 41, 41, 37, 33, 29, 49, 37, 49, 41, 27, 41, 33, 41, 31, 15, 31, 39, 33, 41, 41, 49, 37, 35, 41, 39, 19, 37, 41, 31, 43, 23, 31, 37, 27, 23, 15, 27

Offset

1,2

Comments

The list of rationals {R(n)} is essentially given by A002487(n)/A002487(n+1).

It appears that a(n) is always odd. This has been checked for all primes up to 999983.

Links

Table of n, a(n) for n=1..98.

N. Calkin and H. S. Wilf, Recounting the rationals, Amer. Math. Monthly, 107 (No. 4, 2000), pp. 360-363.

Crossrefs

Subset of A002487.

Sequence in context: A256405 A130149 A053046 * A066658 A005145 A280740

Adjacent sequences: A261176 A261177 A261178 * A261180 A261181 A261182

Keyword

nonn

Author

James Kirk Winkler, Aug 10 2015

Status

approved