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

Author

James Kirk Winkler, Aug 10 2015

Keywords

• nonn

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

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

Crossrefs

Subset of A002487.