Truncatable prime
The trunkierbaren primes (English truncatable primes from Latin truncare, ab-/beschneiden, (ver - ) cut, trim, break, mutilate ) are a subset of the prime numbers that progresses after (right - or left-sided ) cutting their numbers as stay ahead of prim. It differs depending on the direction of the cutting
- Rechtstrunkierbare (R- trunkierbare )
- Linkstrunkierbare (L- trunkierbare ) or
- Both sides trunkierbare ( bitrunkierbare ), ie, both right-and linkstrunkierbare primes.
What are prime numbers trunkierbar depends on the number system used.
Right - trunkierbare primes
Rechtstrunkierbare prime numbers are prime numbers, in which the elimination of any number of the last digits again leads to a prime number.
In the decimal system, for example, the number 317 fulfills this property: 317, 31 and 3 are prime numbers. Thus then is also a 31 rechtstrunkierbare prime.
In the decimal system, there are exactly 83 rechtstrunkierbare primes. The first in this system are the numbers 2, 3, 5, 7, 23, 29 The largest in the decimal is the number 73,939,133.
Rechtstrunkierbare prime numbers are separated also known as " Snowball - Primes ", " Super Prime " and "Prime - Primes ".
27 of 83 decimal rechtstrunkierbaren prime numbers can not be extended by adding additional digits to a larger prime number is, the other 56 are shown by truncation of digits from them.
Linkstrunkierbare primes
Linkstrunkierbare prime numbers are prime numbers,
- Where the digit zero is at any point,
- Where the omission of any number of leading digits again leads to a prime number.
In the decimal system has, for example, the number 632 647 of these properties, as 632 647, 32,647, 2,647, 647, 47 and 7 are prime numbers. In the decimal system, there are exactly 4260 linkstrunkierbare primes. The largest of them is the number 357,686,312,646,216,567,629,137
Both sides trunkierbare primes
In the decimal 2, 3, 5, 7, 23, 37, 53, 73, 313, 317, 373, 797, 3,137, 3,797 and 739 397 the only both left - and rechtstrunkierbaren primes.