Questions tagged [big-numbers]
For questions relating to the computation, estimation and properties of extremely large finite quantities that are not usually used in mainstream mathematics. This is not for questions that just have large numbers; the fact that a number is very large has to affect the question.
275 questions
0 votes
0 answers
63 views
$\text{TREE}(n)$ and well-quasi-ordered sets
I recently got curious about understanding the growth rate of $\text{TREE(n)}$ (and/or the weaker $\text{tree(n)}$ with unlabeled trees). What I understood so far is that the existence and finiteness ...
1 vote
1 answer
84 views
What happens if we add vertex coloring to the Subcubic Graph Number (SSCG)?
In googology many fast grwing functions are defined by graphs, for example the tree function and SCG, I would like to ask about a modification in this functions. A subcubic graph is a finite simple ...
0 votes
0 answers
63 views
Compute the square root of a large power of two
Is there an efficient method to compute the square root of a large power of two with the form $\lfloor\sqrt{2^{2n+1}}\rfloor$? Because $\lfloor\sqrt{2^{2n+1}}\rfloor = \lfloor\sqrt 2 (2^n)\rfloor$, if ...
0 votes
1 answer
219 views
Approximation of blocking probability
I want to compute the blocking probability \begin{align*} \operatorname{B}\left(\rho,m\right) & = \dfrac{\rho^{m}/m!} {\sum_{i= 0}^{m}\rho^{i}/i!} \\[5mm] \mbox{...
1 vote
1 answer
281 views
How many layers of graham's number are required to beat TREE(3)?
I have recently found out about the TREE function, and how TREE(3) is unimaginably large. I also learned about Graham's number, which is a lot smaller than TREE(3). Yet, is there some way to find out ...
1 vote
1 answer
165 views
Simplifying $10^{2380849\cdot 10^{10^{120.20}}-1}$ using Knuth's Up-Arrow notation
Is there a good way to simplify the monstrous number $10^{2380849\cdot 10^{10^{120.20}}-1}$ using Knuth's Up-Arrow notation? I have tried to research how this could be done, but the notation still ...
1 vote
1 answer
117 views
Fibonacci doubling using two squarings?
If $F(n)$ is the $n$-th Fibonacci number, then given $F(n)$ and $F(n-1)$, the classic "fast doubling" way of obtaining $F(2n)$ and $F(2n+1)$ is $$ \begin{align} F(2n) &= F(n) \left(2F(n+...
4 votes
1 answer
162 views
Is there a known generalized Fermat prime with exponent at least $2^{21}$?
In OEIS , the smallest even positive integers $k$ such that $k^{2^n}+1$ is prime are given upto $n=20$. Is there a known prime number with $n\ge 21$ ? Such a number would be very large , so I guess ...
1 vote
1 answer
139 views
Unsolved problems in the relative size of large finite integers
There are a variety of ways to define large numbers (https://en.wikipedia.org/wiki/Large_numbers), such as Graham's number, TREE(3), Rayo's number, etc. Often times we know the relative size of these ...
6 votes
3 answers
252 views
Is $\text{BRANCH}(n)$ finite for $n > 2$?
Is $\text{BRANCH}(n)$ finite for $n > 2$? Define $\text{BRANCH}(n)$ as the maximum length of a string that is composed of at most $n$ unique characters AND meets the following condition: Define a ...
2 votes
1 answer
209 views
How big do hyper-reals get?
Let's assume there is some non-standard model of the reals containing a number $N$ that is larger than any real number. Suppose $\exists N\in {^*}\mathbb{R} ( \forall r\in\mathbb{R}: r<N).$ Now I ...
1 vote
1 answer
104 views
Does this text based Tree Function stay finite?
Define $f(k)$ to be the maximal natural number $n$ such that there exist $n$ strings $s_1,\dots,s_n$ from the alphabet $\{1,2\}$ such that no letter is repeated more than $3$ times in a row, for all $...
0 votes
1 answer
101 views
Does this "tree like" function stay finite?
Or more importantly, does it have a name? The function f(k)=x I have found goes under these rules, There is a group of n strings containing k characters Each string is 1 character longer than the ...
3 votes
1 answer
202 views
Is it possible to calculate the first digits of this number?
Is it possible to calculate the leading decimal digits of $3 \uparrow\uparrow 5\ = 3^{3^{3^{3^3}}} = 3^{3^{7,625,597,484,987}}$? Using currently known methods, this would require knowing the complete ...
2 votes
1 answer
144 views
How to get rid of large numbers in a function?
I study mathematics, and I have a question: I have this math function: f(x) = floor(x^99999 / 10^(floor(log10(x^99999+0.1)) + 1 - 5)) (floor() is rounding down) ...