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# playmath

a boy's math playground; math experiment

Cody Luo(cody@ustc.edu)

## Records:

• 2019-09-02, I proved Goldbach's Conjecture! stage12-try to prov Goldbach Conjecture.ipynb
Note: in Sagemath env to run the codes

Goldbach Conjecture Inequality 1: `gold(n) < prime_pi(n)+sigma(n,0)`
gold(n): the min non-negative integer `g` makes that both `n-g` and `n+g` are primes
prime_pi(n): the count of primes in 1..n
sigma(n,0): the count of n.divisors()

`gold(n) < prime_pi(n), while n>344`

`gold(n) < prime_pi(n)*4395/3449751 ≈ prime_pi(n)*0.0013, while n>57989356`

Goldbach Conjecture Inequality 2: `gold(n) < prime_pi(prime_pi(n)+n)`

• 2019-10-28, I solved 3n+1 Problem! http://a-boy.tk/playmath/stage26-3n%2B1conjecture/proving-3n%2B1-conjecture.html

``````# Syracuse function g(n)
def g(n):
while n%2==0 : n/=2
n=3*n+1
while n%2==0 : n/=2
return n
``````

Collatz-Syracuse Decent Theorem: For any odd positive integer n=2*k+1, it exists s1,`s1<=g(n)<=(3*n+1)/2` to make `nest(g,s1,n)==1`;
Except n=27 or 31, it will get a less number m, m<n before `n` times iterately calling g(x).

``````(n,f(n),g(n),(3*n+1)/2,s(n))
(27, 82, 41, 41, (37, 41))
(31, 94, 47, 47, (35, 39))
``````

Collatz-Odd-Tree1.png

Collatz正奇数回归树生成规则(Collatz-Odd-Tree Generation Rule):

1. x在完全的Collatz-Odd-Tree中是叶节点 iff (x%3==0)
2. 每个节点的长子由 `v(x)=(2*x-1)/3 or (4*x-1)/3` 产生
3. 其余每个小兄弟由 `h(x)=4*x+1` 迭代陆续产生, 因为 3(4x+1)+1 = 12x+4 = 4*(3*x+1) 。

• 2010-02-04, I discovered Prime-Gap-Inequality: The i-th prime gap `p[i+1]-p[i]<=i` In other words, `range(n,n+primepi(n))` contains one or more primes. So, the i-th prime `p[i]<=1+2+...+ i-1 + p[1] = i*(i-1)/2 +2`

• I discovered Bread Curve and Bread Model by chance in 2011:

``````def r(theta):= nest(sin,theta,1000)
polar_plot(r(theta),(theta,0,2*PI))

``````

• before2011/果中的泪滴.png

• 2022-02-07, I improved Oppermann's Conjecture!

NextPrime-Of-Square-Inequality: `next_prime(n^2) - n^2 <= 1+euler_phi(n)`

## idea:(mailto:a_boy@live.com)

• Goldbach-Triangle: every item is the average of top and right primes.
3
4 5
5 6 7
7 8 9 11
8 9 10 12 13
10 11 12 14 15 17
11 12 13 15 16 18 19
13 14 15 17 18 20 21 23
16 17 18 20 21 23 24 26 29
17 18 19 21 22 24 25 27 30 31
20 21 22 24 25 27 28 30 33 34 37
• n>=3, let `p=nextprime(n!)-n!` , then p is always prime or 1, because p is less than ` nextprime(n)^2` , very often `p<n^2` .

• denote S(k,v):=RamseyNumber(k+1,v+1)-1 . Conjecture: for any integer v>=2, S(2,v)%5 in {0,2,3}, here S(2,v)=RamseyNumber(3,v+1)-1 . That is to say, RamseyNumber(3,v+1) can NOT be the form 5k or 5k+2

``````m	n	R(m,n)	Reference
3	3	6	Greenwood and Gleason 1955
3	4	9	Greenwood and Gleason 1955
3	5	14	Greenwood and Gleason 1955
3	6	18	Graver and Yackel 1968
3	7	23	Kalbfleisch 1966
3	8	28	McKay and Min 1992
3	9	36	Grinstead and Roberts 1982
3	10	[40, 43]	Exoo 1989c, Radziszowski and Kreher 1988
3	11	[46, 51]	Radziszowski and Kreher 1988
3	12	[52, 59]	Exoo 1993, Radziszowski and Kreher 1988, Exoo 1998, Lesser 2001
3	13	[59, 69]	Piwakowski 1996, Radziszowski and Kreher 1988

5	5	[43, 49]	Exoo 1989b, McKay and Radziszowski 1995
6	6	[102, 165]	Kalbfleisch 1965, Mackey 1994
7	7	[205, 540]	Hill and Irving 1982, Giraud 1973
``````

Guess: for any ineteger n>=1, RamseyNumber(n+1,n+1)-1 = S(n,n) contains only the factors of Fermat Numbers `F[m]=2^2^m+1`, {1,2,3,5,17,257,641,65537,...} S(2,2)=5, S(3,3)=17, I guess S(4,4)=45

• try to prove Twin Prime Conjecture
``````    1. Method 1: If a prime gap subsequence repeats twice, then it will occur infinitely times.
such as {2}, {4},{2*k},{2,4,2},{6,6}...
1. Method 2: by using modern database function `groupby` on prime gap sequence, ...
Observing prime gap frequency distribution for primes up to some big integer N0 .
Peaks occur at multiples of 6. And the ratio of {2}s to {6}s will be great than a const(0.5 ?).
1, 2, 2, 4, 2, 4, 2, 4, 6, 2, 6, 4, 2, 4, 6, 6, 2, 6, 4, 2, 6, 4, 6, 8, 4, 2, 4, 2, 4, 14, 4, 6, 2, 10, 2, 6, 6, 4, 6, 6, 2, 10, 2, 4, 2, 12, 12, 4, 2, 4, 6, 2, 10, 6, 6, 6, 2, 6, 4, 2, ... (sequence A001223 in the OEIS).
``````
• define the integer sequence `x[n+1]:=x[n]^2+1`, if take x[0]>1, then x[5] is very often composite.

• 定义:二密分解 `n=q1*q2` , `q1`取小于或等于`√n`的最大因数, `q2`取大于或等于`√n`的最小因数。 是否值得尝试，使用二密分解或p-密分解的一些性质证明费马大定理? 抛开Wiles的复杂理论和过程?

• OPPC(Odd Primes Position Constant) 奇质位常数，`2*k-1`如果是质数则二进制小数点后第k位为1，否则为0

``````const OPPC = 0.0111 0110 1101 0011
1357 9
``````

## Question

• Ultra-Primes-Conjecture
``````There exists infinitely many primes formed of 2^(F[n!+1])-1 . here 2^p-1 is Mersenne number, F[n+2]=F[n+1]+F[n], 0,1,1,2,3,5,8,... is Fibonacci number, n! is factorial.

https://math.stackexchange.com/questions/3503947

2^F[2!+1]-1 = 3, 2^F[3!+1]-1= 2^13-1= 8191 are two known Ultra-Primes! I guess after 3, 8191 there are more prime heros!
``````
• I think there exists Inertia Law and Polar Method for integer sequences. 整数数列的惯性定理和极性定理

#### math tools

• Mathematica : .nb is Mathematica notebook
• Sagemath : .ipynb is Jupyter notebook, most of *.ipynb files in a-boy/playmath are used Sagemath, to view by Jupyter nbviewer, but to run codes only in Sagemath env; .sagews is Sagemath worksheet
• Maple
• GeoGebra
• Octave
• MathType
• SketchUp

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