Definition:Right-Truncatable Prime
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Definition
A right-truncatable prime is a prime number which remains prime when any number of digits are removed from the right hand end.
Sequence
The sequence of right-truncatable primes begins:
- $2, 3, 5, 7, 23, 29, 31, 37, 53, 59, 71, 73, 79, 233, 239, 293, 311, 313, 317, 373, 379, \ldots$
Examples
$73 \, 939 \, 133$ is a Right-Truncatable Prime
| \(\ds \) | \(\) | \(\ds 73 \, 939 \, 133\) | is the $4 \, 335 \, 891$st prime | |||||||||||
| \(\ds \) | \(\) | \(\ds 7 \, 393 \, 913\) | is the $501 \, 582$nd prime | |||||||||||
| \(\ds \) | \(\) | \(\ds 739 \, 391\) | is the $59 \, 487$th prime | |||||||||||
| \(\ds \) | \(\) | \(\ds 73 \, 939\) | is the $7296$th prime | |||||||||||
| \(\ds \) | \(\) | \(\ds 7393\) | is the $939$th prime | |||||||||||
| \(\ds \) | \(\) | \(\ds 739\) | is the $131$st prime | |||||||||||
| \(\ds \) | \(\) | \(\ds 73\) | is the $21$st prime | |||||||||||
| \(\ds \) | \(\) | \(\ds 7\) | is the $4$th prime |
$\blacksquare$
Various Number Bases
Right-Truncatable Prime/Various Number Bases
Also see
- Results about right-truncatable primes can be found here.
Sources
- 1997: David Wells: Curious and Interesting Numbers (2nd ed.) ... (previous) ... (next): $73,939,133$
- Weisstein, Eric W. "Truncatable Prime." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/TruncatablePrime.html