# Tag Archives: Prime Numbers

## Word puzzle| A = 2, B = 3, C = 5, …, Z = 101

Form words that are very close to   for example the word ADD A = 2   and   D = 7 then multiply the prime numbers representing the word ADD ADD   =   2 * 7 … Continue reading

Posted in Word Puzzle | Tagged | 5 Comments

## 19 primes embedded in a cube

Consider     and embedded in this number are 19 primes reading left to right thus, 3,   7,   31,   47,   73,   83,   331,   733,   839,   983,   3169,   4733,   … Continue reading

Posted in Number Puzzles | Tagged , | 10 Comments

## Consecutive primes (p,q): 1/a + 1/b = q/p, (a,b) positive intgers

Find all positive integer pairs     such that where     and     are consecutive primes with     for example,   1/a   +   1/b   =   2/3 a = 2,          b … Continue reading

## When concatenation of consecutive primes is prime

2   ||   3   =   23 2   ||   3   ||   5   ||   7   =   2357 11   ||   13   ||   17   =   … Continue reading

Posted in Number Puzzles | Tagged , | 6 Comments

## Puzzle | Five 2-digit numbers

Paul offered the following puzzle: A, B, C, D and E are 2-digit numbers in any order, A, B, C, D and E are some multiple of a prime number between 2 and 9 all different. A, B, C, … Continue reading

## Primes which are the difference of two consecutive cubes

,    where

## Prime num3er puzzle: groups of 3

– Select a set of consecutive prime numbers. – Break it into groups of three such that each group sums up to a prime number. – Write the digits reversed of each sum – Find sums before and after … Continue reading

Posted in Number Puzzles | Tagged | 3 Comments

## Pandigital | three prime numbers

Let   ,   ,     be three prime numbers. multiplying the first by 7,   the second by 8 and the third by 9, so we have ,     and   with . The combined … Continue reading

Posted in Number Puzzles | Tagged , | 2 Comments

## Sequence of prime numbers: p_(k+1) – (p_k + p_(k-1))= A

Find a sequence of prime numbers ,   ,   ,   … ,   ,   ,   ,   … ,   such that and                         … Continue reading

Posted in Number Puzzles | Tagged , | 1 Comment

## When sum of three 3-digit prime numbers is prime

Let   P, Q,   and   R   be three 3-digit prime numbers whose sum is prime.   P, Q,   and   R   are distinct.     Find more solutions             … Continue reading

Posted in Number Puzzles | Tagged | 4 Comments