5^n-4n-1 is divisible by 16 for allnatural numbers n
更新1:
1^2/1x3+2^2/3x5+3^2/5x7+....+^2/(2-1)(2+1)=n(n+1)/2(2n+1)
更新2:
上面果個錯左... prove, by mathematical induction,that the following propositions are true 1^2/1x3+2^2/3x5+3^2/5x7+....+n^2/(2n-1)(2n+1)=n(n+1)/2(2n+1)
