WWGD
Science Advisor
Homework Helper
- 7,742
- 12,931
One of my favorites: For n>2 , every number 1 less than a square is composite:
##n^2 -1 =(n+1)(n-1) ##. You get the actual factorization for free.
Example: ##899=900-1 =(30+1)(30-1)=31 *29##
##n^2 -1 =(n+1)(n-1) ##. You get the actual factorization for free.
Example: ##899=900-1 =(30+1)(30-1)=31 *29##


