A265079 Numbers n such that the Crandall number C = A262961(n) has exactly one prime divisor p >= n/2.

3, 5, 7, 9, 11, 33, 36, 49, 453, 727, 1560, 1569, 1627, 5078, 6605, 17663, 27281, 29298, 29708, 39509, 98653

Offset: 1

Author

N. J. A. Sloane, Dec 30 2015

Keywords

• nonn
• more

Comments

If a Crandall number C = A262961(n) is an even semiprime, then n is a term of this sequence. - Altug Alkan, Dec 30 2015

Examples

			5 is a term because A262961(5) = 302 and its prime divisors are 2, 151 and only 151 >= 5/2.
		

Links

• David Broadhurst, Crandall Memorial Puzzle, Oct 04, 2015.
• David Broadhurst, Crandall Memorial Puzzle [Cached copy, with permission]
• David Broadhurst, Crandall memorial puzzle: solution and heuristics
• David Broadhurst, Crandall memorial puzzle: solution and heuristics [Cached copy, with permission]
• David Broadhurst, Feynman integrals, L-series and Kloosterman moments, arXiv:1604.03057, 2016.

Crossrefs

Cf. A262961.