Discussion about math, puzzles, games and fun. Useful symbols: ÷ × ½ √ ∞ ≠ ≤ ≥ ≈ ⇒ ± ∈ Δ θ ∴ ∑ ∫ • π ƒ ¹ ² ³ °
 

You are not logged in. #1 20050810 01:40:16
A prime puzzleLet n be a nonnegative integer. Is 14^n + 11 ever a prime number? 2 + 2 = 5, for large values of 2. #2 20050810 02:19:50
Re: A prime puzzleAs n increases, 14^n's last digit alternates between 4 and 6, with the exception of n=0. Adding 11 to 4 gives 15, and as all numbers that end in 5 are divisible by 5, 14^n+11 is divisible by 5 for all odd values of n. Why did the vector cross the road? It wanted to be normal. #3 20050810 15:05:45
Re: A prime puzzleDigital roots of 14^n Character is who you are when no one is looking. #4 20050812 04:24:25
Re: A prime puzzleThat works! 2 + 2 = 5, for large values of 2. 