Other Factordb Problems

[chris2be8]

Originally Posted by Happy5214

Does Markus's script know to factor these large products algebraically first? That would be a huge help.

I emailed him about this, he replied:

Hello Chris,

looks like there are tons of numbers which are just the product of
several expressions. I'll run a script for these now, might take a while.

Markus

This will clear out a lot of junk. But probably produce a load of small entries for the various expressions that make up the junk. But at least some of them will be SNFS targets.

[RichD]

This really slows down work in the database.

[sweety439]

There were many small composites < 10^18 (from a bug) in Oct 2021, and all of them had been deleted, but there were also many small primes < 10^18, also from the same bug, but why they have not been deleted? I think they also need to be deleted.

[Happy5214]

Along with deleting those bad primes, please just delete/disable the modulo operator altogether if that hasn't been done already. It obviously isn't implemented correctly, it's not particularly useful, and tons of bogus data has resulted from its use.

[sweety439]

Originally Posted by Happy5214

Along with deleting those bad primes, please just delete/disable the modulo operator altogether if that hasn't been done already. It obviously isn't implemented correctly, it's not particularly useful, and tons of bogus data has resulted from its use.

Not delete the modulo operator (%), but just fix this operator, also suggest lower case letters for variables, upper case letters for these functions: (delete these operators: "!!" = double factorial and "##" = product of first n primes, suggest to use "n!m" for the m-factorial function of n (multifactorial))

A      n! - (n-1)! + (n-2)! - ... 1!      A005165
B      Bell numbers      A000110
C      Catalan numbers      A000108
D      Distinct partition numbers      A000009
E      Euler zigzag numbers      A000111
F      Fermat numbers      A000215
G      Fubini numbers      A000670
H      H(m,n) = n-th m-Fibonacci numbers      A000045 A000129 A006190 A001076 ...
I      I(m,n) = n-th m-step Fibonacci numbers      A000045 A000073 A000078 A001591 ...
J      Coefficients of modular function j as power series in q = e^(2 Pi i t)      A000521
K      1! + 2! + 3! + ... + n!      A007489
L      L(m,n) = n-th m-Lucas numbers      A000032 A002203 A006497 A014448 ...
M      Mersenne numbers      A000225
N      N(m,n) = n!_(m) = m-factorial of n
O      O(m,n) = m-th cyclotomic polynomial evaluated at n
P      Partition numbers      A000041
Q      Perrin numbers      A001608
R      R(m,n) = repunit in base m with length n
S      S(m,n) = (Smarandache numbers) the concatenate the first n integers in base m
T      Ramanujan's tau function      A000594
U      U(n,p,q) = Lucas sequence U_n(p,q)
V      V(n,p,q) = Lucas sequence V_n(p,q)
W      W(m,n) = (Wolstenholme numbers) numerator of 1 + 1/(2^m) + 1/(3^m) + ... + 1/(n^m)
X      X(m,n) = (Smarandache-Wellin numbers) the concatenate the first n primes in base m
Y      Y(m,n) = n-th m-step Lucas numbers      A000032 A001644 A073817 A074048 ...
Z      Motzkin numbers      A001006
!      Factorial
#      Primorial
%      Modulo operator
\      Integer division
@      n@ = n-th prime
&      Narayana's cows sequence      A000930
$      Padovan sequence      A000931

[sweety439]

Originally Posted by Happy5214

Unless you're also immediately posting the Primo certs or doing P-1/P+1 proofs, please don't. Additions like those create extra work for the cert elves and are part of the overall problem.

P-1 and P+1 are "integer factoring" algorithm

N-1 and N+1 are "primality testing" algorithm

They are different (but I doubt whether they are related? After all, "integer factoring" algorithm also has ECM, and "primality testing" algorithm also has ECPP, and both of them uses elliptic curves, however, they are found by different people, P-1 is by Pollard, P+1 is by Williams, N-1 is by Pocklington, N+1 is by Morrison)

[Batalov]

Originally Posted by sweety439

wiki
wiki
They are different

The revenge of ...

[Happy5214]

Originally Posted by sweety439

P-1 and P+1 are "integer factoring" algorithm

N-1 and N+1 are "primality testing" algorithm

[,,,]

I was late for a meeting when I wrote that and didn't have time to proofread. I don't need the extended response.

Originally Posted by sweety439

Not delete the modulo operator (%), but just fix this operator [...]

Can you (or anyone) demonstrate any useful purpose for this operator that justifies its continued existence on this website, especially in the face of all the trouble it's caused? IMO all entries using it need to be purged.

[Stargate38]

I know of a reason to keep it. Since we don't have a built-in floor or ceiling function, we can represent it as floor(a/b)=(a-(a%b))/b, and ceil(a/b)=(a-(a%b))/b+1. We can use this to calculate floor(M521/10^100): http://www.factordb.com/index.php?id...00000824396765. That's far shorter than "(M521-4463459185543183397656052122559640661454554977296311391480858037121987999716643812574028291115057151)/10^100".

[sweety439]

Originally Posted by Stargate38

I know of a reason to keep it. Since we don't have a built-in floor or ceiling function, we can represent it as floor(a/b)=(a-(a%b))/b, and ceil(a/b)=(a-(a%b))/b+1. We can use this to calculate floor(M521/10^100): http://www.factordb.com/index.php?id...00000824396765. That's far shorter than "(M521-4463459185543183397656052122559640661454554977296311391480858037121987999716643812574028291115057151)/10^100".

I suggest to add "\" (integer division)

Also, factordb has "n##" (product of the first n primes) but does not have "n@" (the n-th prime), I really do not know why, it is not reasonable! Thus I think that factordb should add "n@" for the n-th prime.

[charybdis]

There is a common theme here:
When people post here, nothing gets done. When people email Markus, he pays attention. It's pretty clear that Markus doesn't read this thread.

In other words, for those who would like the modulo operator fixed/removed, I suggest dropping Markus an email.
(Sweety: please don't spam him with lots of stupid suggestions. That might make him less willing to pay attention to serious suggestions.)