Now, I have written known facts about numbers in question in
my paper published in the journal Notes on Number
Theory and Discrete Mathematics; not only that, I tried to derive some
properties of these numbers. I'll be glad for your eventual response to this paper.
The link to it is here.
I assume that my puzzles will mainly be focused on machine use / break. Sure, writing good code is a commendable job. However, more mathematical procedures, such as proofs, are welcome, too. Thank you for your interest and feedbacks. Miroslav Kureš
úterý 9. července 2019
sobota 15. prosince 2018
2019
Sure, the number 2019 has a lot of great properties. For
example, 2019 is the least number having
six different representations as a sum of three squares of prime numbers.
2019 = 232+232+312
2019 = 172+192+372
2019 = 112+232+372
2019 = 132+132+412
2019 = 72+172+412
2019 = 72+112+432
There
a lot of numbers having six different representations as above, not seven or
more. They form a sequence 2019, 2091, 2499, 3099, 3219, 3339, 3579,
3939, 4011, ... E.g., 4011 = 312 + 372 +
412 = 292 + 312 + 472 =
112 + 412 + 472 = 192 +
292 + 532 = 132 + 192 +
592 = 112 + 132 + 612.
čtvrtek 6. září 2018
Puzzle 1: Sum of Powers of Primes / Results - 2
Dana
Jacobsen has published a short code for (P2) in the Perl language on mersenneforum. He notes that testing
up to 109 takes 90 minutes.
středa 5. září 2018
Puzzle 1: Sum of Powers of Primes / Results - 1
The mersenneforum
user, nicknamed a1call, has
announced the finding of a new number with the (P2) property. It is the number 9634877 (Sep 3rd, 2018). Excellent work!
čtvrtek 30. srpna 2018
Puzzle 1: Sum of Powers of Primes
The
whole story began around the
turn of the millennium when Carlos Rivera
observed that 39 is a number with the
following property:
(P1) A non-prime number equal to the sum of consecutive primes from the least prime factor to the largest prime factor.
Of course, 39 = 3 * 13 = 3 +
5 + 7 + 11 + 13.
It
is not difficult to verify that 10, 155 and 371 are other
numbers with this property. Later (Jul. 2000), Jud McCranie found the 5th
number:
2935561623745 = 5 * 19 * 53 * 61 * 9557877 = 5
+ 7 + 11 + ... + 9557877.
454539357304421 = 3536123 * 128541727 =
3536123 + 3536129 + 3536131 + ... + 128541727.
So, six numbers
with the property (P1) are known up to now. One can find them in the Online
Encyclopedia of Integer Sequences under the code A055233.
We change the
property somewhat now:
(P2) A non-prime-square number equal to the
sum of squares of consecutive primes from the least prime factor to the largest prime
factor.
The smallest
number with this property is 315797.
Indeed,
315797 = 31 * 61 *
167 = 312 + 372 + 412 + ... + 1672.
Question
A: Find other numbers with the property (P2).
We can continue.
(P3) A non-prime-cube number equal to the sum
of cubes of consecutive primes from the least prime factor to the largest prime factor.
In this case, there
is a nice solution: 160.
160 = 25
* 5 = 23 + 33 + 53.
Question
B: Find other numbers with the property (P3).
And finally:
Question C: The first, second and third powers of primes can be generalized to any n-th power. Find also any numbers for n>3.
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