A prime number is called 'strange' if either it is a one-digit prime, or if each of the numbers obtained by removing its first digit or its last digit are themselves strange primes. How many strange primes are there?
Kindly provided by UKMT 'STRANGE' Primes...
A prime number is called 'strange' if either it is a one-digit prime, or if each of the numbers obtained by removing its first digit or its last digit are themselves strange primes. How many strange primes are there?
5 Comments
|
Puzzle Ideas
If you have an idea for puzzle of the month, then please do let me know. Archives
September 2017
Don't forget to check out 'Teach Further Maths' - PowerPoints for Teachers and Students of A-Level Further Maths ...and the brilliant NEW educational card game 'Maths Trumps' |