A289662 a(n) is the smallest m such that p = n-th popular prime = A385503(n) is uniquely popular on the interval [2,m] or -1 if p is never uniquely popular.

2, 12, 80, 196, 1638, 4864, 22425, 46500, 109779, 158625, 603564, 2552416, 2620142, 2627250, 41163747, 237398795, 1966466950, 13690729828, 64322158656, 79838739611, 220355987735, 232268774850, 618745972214, 1882062476406, 9607713772982, 19364051829855, 26393150937218, 37636607806688, 114514665167797, 173974642809066, 228013323978930, 259772858868378, 284600479573629, 644741545246282

Offset: 1

Author

N. J. A. Sloane, Jul 25 2017

Keywords

• nonn

Comments

See A385503 for further links and information.

Links

• Nathan McNew, Popular values of the largest prime divisor function (corrected version), page 16, November 2015.

Crossrefs

Cf. A006530, A385503, A125624, A289661-A289665.

Extensions

Deleted "first" from definition. - N. J. A. Sloane, Oct 03 2019

Edited, and terms updated from revised version of McNew, by Peter Munn, Jul 04 2025