30 semiprimes, each less than 10
8, form an arithmetic sequence with strictly positive common difference.
Determine all of them.
Note: A semiprime is the product of exactly two primes.
*** For an extra challenge only, find a semi-analytic solution (simple calculator + p&p) to this puzzle.
For L=30, R=10^8, unless the bound is wildly generous, there must be multiple prime factors of entries in S that are each of the order of 10^6.
Setting the actual problem aside(!) isn't trial factorisation of these factors alone pretty much beyond the reach of p&p?
I shall be intrigued to see KS's p&p solution!
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Posted by broll
on 2022-11-20 23:43:53 |
Really?
