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A265079 Numbers n such that the Crandall number C = A262961(n) has exactly one prime divisor p >= n/2. 2
3, 5, 7, 9, 11, 33, 36, 49, 453, 727, 1560, 1569, 1627, 5078, 6605, 17663, 27281, 29298, 29708, 39509, 98653 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

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

LINKS

Table of n, a(n) for n=1..21.

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.

EXAMPLE

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

CROSSREFS

Cf. A262961.

Sequence in context: A004156 A081936 A238795 * A092361 A029950 A061507

Adjacent sequences:  A265076 A265077 A265078 * A265080 A265081 A265082

KEYWORD

nonn,more

AUTHOR

N. J. A. Sloane, Dec 30 2015

STATUS

approved

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Last modified August 15 01:47 EDT 2020. Contains 336485 sequences. (Running on oeis4.)