Prime Finder

數百萬款最新的 Android 應用程式、遊戲、音樂、電影、電視節目、書籍、雜誌等項目盡在其中，歡迎隨時隨地透過您的各種裝置取得。

Prime Finder lets you find primes of all sizes, and primes that follow formulas and simple digit patterns.

This App has 6 main options:

1) test any number to see if it is prime;

2) find primes with any number of digits;

3) find primes near any number;

4) find primes that follow a digit pattern like

11, 111, 1111, 11111, or 7, 97, 997, 9997 ... etc.;

5) find primes that follow a formula, like

n^2 + 1 for n = 1, 2, ... .

6) make several expressions be prime simultaneously,

like n and n + 2 (twin primes).

These options can handle numbers up to 10,000 digits.

This App also contains data on the first 100 million primes. This App can:

7) find the nth prime (n can be as large as 100 million);

8) count the number of primes up to x (x can be as large as 2,038,074,743).

Features:

1) this App uses the fast BPSW primality test to check whether a number is prime;

if it is not prime and has 30 or fewer digits, this App will factor it into primes;

2) you can copy the output to the device's clipboard;

3) it's free, has no ads, no special permissions are requested;

4) you can cancel a long calculation at any time;

5) built-in Help text has information about primes and prime testing,

along with links to more detailed Wikipedia articles.

If you find a bug, email me and I'll get to work on fixing it.

If you have a suggestion for a new feature, email me and I'll consider adding it.

This App has been tested on a Galaxy Tab, and Galaxy ii, 3, and 4 devices.