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Is there a name for numbers whose only factors are primes and semiprimes but may not be primes in themselves? (lemmy.world)

submitted 10 months ago by [email protected] to c/[email protected]

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And for how long can this pattern continue?

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[–] [email protected] 8 points 10 months ago

https://en.m.wikipedia.org/wiki/Almost_prime

[–] [email protected] 3 points 10 months ago (1 children)

How long can this pattern continue? My guess is forever, since you can just multiply a prime by the next prime (2x3=6), then take that prime, and multiply it by the next (3x5=15) and so on. So it seems to me like there's an infinite number of these kinds of primes, unless I'm not understanding you correctly.

[–] [email protected] 0 points 10 months ago

I guess they mean a naming pattern: like hemi-demi-semi-primes

(That's how we do it in music, over on my side of the 'pond': but we get to hemi-demi-semi-quavers then (afaik) give up because no one cares for more!)

[–] [email protected] 2 points 10 months ago

I think numbers like these would be very useful in cryptography, where the higher the power of a prime factor sometimes, the easier it is to factor it. Some probably obscure probability calculations and so on