> Sloane calls them “memorable” primes
Excluding 11 seems arbitrary here.
Prime numbers so memorable that people hunt for them
21–30 of 106 posts
Re: Prime numbers so memorable that people hunt for them
#22https://en.wikipedia.org/wiki/Belphegor%27s_prime "666" with 13 0's on either side and 1's on the ends.
"on both sides" because "on either side" to me meant it may be duo of 1-13zeros-6661 and 1666-13zeros-1. More for those who don't click the link, other Belphegor primes numbers are with the following number of zeros in both ends (and 1 to cap off the ends): 0, 13, 42, 506, 608, 2472, 2623, maybe more.
"to either side" or "on either side" commonly means "on both sides"
"Either" has two meanings:
- verb-wise, it separates different options (you can have either X or Y)
- noun-wise, it refers to two similar groups (there was no light on either side of the bridge, or, conversely, the bridge was lit on either side)
Re: Prime numbers so memorable that people hunt for them
#23https://en.wikipedia.org/wiki/Belphegor%27s_prime "666" with 13 0's on either side and 1's on the ends.
It also works with no zeros, or all sorts of other number of zeros. Dude basically just added zeros until the number got cooler.
The palindromic Belphegor numbers https://oeis.org/A232449
Indices of Belphegor primes: numbers k such that the decimal number https://oeis.org/A232448
Re: Prime numbers so memorable that people hunt for them
#24Reminds me the demonstration that all whole numbers are interesting in a way or another. Being memorable in this case is not so much about memory but about having an easy to notice pattern of digits, or a clear trivial algorithm to build them.
https://en.wikipedia.org/wiki/Interesting_number_paradox > The interesting number paradox is a humorous paradox which arises from the attempt to classify every natural number as either "interesting" or "uninteresting". The paradox states that every natural number is interesting.[1] The "proof" is by contradiction: if there exists a non-empty set of uninteresting natural numbers, there would be a smallest uninterestin…
https://en.wikipedia.org/wiki/Taxicab_number
The name is derived from a conversation ca. 1919 involving mathematicians G. H. Hardy and Srinivasa Ramanujan. As told by Hardy:
I remember once going to see him [Ramanujan] when he was lying ill at Putney. I had ridden in taxi-cab No. 1729, and remarked that the number seemed to be rather a dull one, and that I hoped it was not an unfavourable omen. "No," he replied, "it is a very interesting number; it is the smallest number expressible as the sum of two cubes in two different ways."
Re: Prime numbers so memorable that people hunt for them
#25Reminds me the demonstration that all whole numbers are interesting in a way or another. Being memorable in this case is not so much about memory but about having an easy to notice pattern of digits, or a clear trivial algorithm to build them.
https://en.wikipedia.org/wiki/Interesting_number_paradox > The interesting number paradox is a humorous paradox which arises from the attempt to classify every natural number as either "interesting" or "uninteresting". The paradox states that every natural number is interesting.[1] The "proof" is by contradiction: if there exists a non-empty set of uninteresting natural numbers, there would be a smallest uninterestin…
Can also consider variations of this such as https://en.wikipedia.org/wiki/Berry_paradox or even the very general https://en.wikipedia.org/wiki/Sorites_paradox
Re: Prime numbers so memorable that people hunt for them
#26Earlier quoted context omitted.
"on both sides" because "on either side" to me meant it may be duo of 1-13zeros-6661 and 1666-13zeros-1. More for those who don't click the link, other Belphegor primes numbers are with the following number of zeros in both ends (and 1 to cap off the ends): 0, 13, 42, 506, 608, 2472, 2623, maybe more.
"to either side" or "on either side" commonly means "on both sides" "Either" has two meanings: - verb-wise, it separates different options (you can have either X or Y) - noun-wise, it refers to two similar groups (there was no light on either side of the bridge, or, conversely, the bridge was lit on either side)
(Native speaker) i read either in the sense of logical or, so one side alone (tegardless of which side) or both sides at once.
Interesting how varied the ohrasing can be read, though!
Re: Prime numbers so memorable that people hunt for them
#27Since divisibility by 2 and 5 is such a problem, why not look for memorable numbers in prime base, like base 7 or base 11?
Why do we care about base 10 ? Because we have five digits per appendage ? BFD. Accident of evolution.
What about palindromes in binary ? That's about as close to a mathematical ideal as we could get. Yes?
Let's see. decimal 11 = binary 1011, its palindrome = 1101 = decimal 13, GOLD!
Re: Prime numbers so memorable that people hunt for them
#28Since divisibility by 2 and 5 is such a problem, why not look for memorable numbers in prime base, like base 7 or base 11?
Re: Prime numbers so memorable that people hunt for them
#29ChatGPT o1: https://chatgpt.com/share/678feedb-0b2c-8001-bd77-4e574502e4...
> Thought about large prime check for 3m 52s: "Despite its interesting pattern of digits, 12,345,678,910,987,654,321 is definitely not prime. It is a large composite number with no small prime factors."
Feels like this Online Encyclopedia of Integer Sequences (OEIS) would be a good candidate for a hallucination benchmark...
Re: Prime numbers so memorable that people hunt for them
#30A few other memorable primes: https://math.stackexchange.com/questions/2420488/what-is-tri... 888888888888888888888888888888 888888888888888888888888888888 888888888888888888888888888888 888111111111111111111111111888 888111111111111111111111111888 888111111811111111118111111888 888111118811111111118811111888 888111188811111111118881111888 888111188811111111118881111888 888111888811111111118888111888 8881118888811111…
These are great! I wonder if Carl Sagan knew about them when writing Contact. The movie doesn't go into the part of the book that is relevant here (trying to avoid spoilers but if you read the book you know!)
Here's a previous HN submission about finding Waldo in pi (spoiler: only by cheating significantly re what counts as "Waldo"): https://news.ycombinator.com/item?id=30872676
I googled around trying to figure out what year James McKee created the Trinity Hall prime. The internet is (IMO) presenting it mainly as some kind of Wonder of the Ancient World — with the date of creation conveniently filed off. The first post below claims that the year McKee left Cambridge and created the prime was 1996. It seems to have hit peak internet presence only in the 2010s, though, so I wish there were an authoritative source to confirm (or deny) the 1996 date.
https://www.bradyharanblog.com/blog/artistic-prime-numbers
https://www.futilitycloset.com/2017/09/10/trinity-hall-prime...
https://www.futilitycloset.com/2020/01/12/more-prime-images/