## Search found 32 matches

- Sun Dec 24, 2017 9:09 am
- Forum: Number
- Topic: Prime generation
- Replies:
**3** - Views:
**9491**

### Prime generation

If you add 2,4,6..... To these four prime numbers then you will get a series of primes 5- 5,7,11,17,25 11-11,13,17,23,31,41,53,67,83,101,121 17- 17,19,23,29,37,47,59,73,89,107,127,149,173,199,227,257,289 41- 41,43,47,53,61,71,83,97,113,131,151,173,197,223,251,281,313,347,383,421,461,503,547,593,641,...

- Fri Sep 15, 2017 5:47 pm
- Forum: Recreational
- Topic: How to factor
- Replies:
**8** - Views:
**8592**

### Re: How to factor

As i have learnt sieving has limits. What if i want to factor a 20 digit number or say a 50 digit number. How would I do it?

- Tue Sep 12, 2017 3:42 am
- Forum: Clarifications on Project Euler Problems
- Topic: Problem 609
- Replies:
**10** - Views:
**4736**

### Re: Problem 609

Thank you very much

- Mon Sep 11, 2017 6:18 pm
- Forum: Clarifications on Project Euler Problems
- Topic: Problem 609
- Replies:
**10** - Views:
**4736**

### Re: Problem 609

You mean if n=4 then following pi sequences can be created

4,2,1 and 4,2 and only one of them have one not prime, k=c(u), which is 4,2.

Is it? Correct me if I'm wrong.

If that's correct help me with last doubt. Who will choose values of n and k?

4,2,1 and 4,2 and only one of them have one not prime, k=c(u), which is 4,2.

Is it? Correct me if I'm wrong.

If that's correct help me with last doubt. Who will choose values of n and k?

- Mon Sep 11, 2017 8:18 am
- Forum: Clarifications on Project Euler Problems
- Topic: Problem 609
- Replies:
**10** - Views:
**4736**

### Problem 609

I didn't understand the following line :-

Let p(n,k) be the number of π sequences u for which $u_0$ ≤n and c(u)=k .

can you please clear it to me with a suitable example?

Let p(n,k) be the number of π sequences u for which $u_0$ ≤n and c(u)=k .

can you please clear it to me with a suitable example?

- Mon Sep 11, 2017 8:02 am
- Forum: Recreational
- Topic: How to factor
- Replies:
**8** - Views:
**8592**

### Re: How to factor

Hi,

I want to know how to get all the prime factors of a number.

Recently I have learnt sieving from Muthu, which is an excellent method. still looking for more efficient methods.

- Sat Sep 09, 2017 4:20 pm
- Forum: Recreational
- Topic: How to factor
- Replies:
**8** - Views:
**8592**

### Re: How to factor

To be specific the problem requires all the factors and not only the prime ones so-

1 how would it help by taking the sqrt(n)

2 all factors are needed(not only the primes)

3 i dont know how to use sieve

And finally in india the power supply has never run for a day continuously

1 how would it help by taking the sqrt(n)

2 all factors are needed(not only the primes)

3 i dont know how to use sieve

And finally in india the power supply has never run for a day continuously

- Sat Sep 09, 2017 9:07 am
- Forum: Recreational
- Topic: How to factor
- Replies:
**8** - Views:
**8592**

### How to factor

The only method of factoring that i know is trial division. When i used it in solving a problem i got to know how bad it is. As the number increases the number of factors increses too. Even after calculating for two hours the number reached was not even one fourth of destined number. Help me please....

- Fri Sep 08, 2017 12:12 pm
- Forum: Recreational
- Topic: Suggest me a book
- Replies:
**14** - Views:
**15130**

### Re: Suggest me a book

Anything on number theory? Which branch do you like?

- Fri Sep 08, 2017 12:11 pm
- Forum: Recreational
- Topic: Suggest me a book
- Replies:
**14** - Views:
**15130**

### Re: Suggest me a book

Thanks

- Thu Sep 07, 2017 9:49 am
- Forum: Recreational
- Topic: Suggest me a book
- Replies:
**14** - Views:
**15130**

### Suggest me a book

Which books would you prefer if i want to learn about number theory, factoring, different methods of finding primes and a great book on maths?

- Thu Sep 07, 2017 9:44 am
- Forum: Recreational
- Topic: hello from indonesia
- Replies:
**1** - Views:
**6317**

### Re: hello from indonesia

Good for you. Which language do you use?