(1*2*4+2*4*8+`````+n*2n*4n/1*3*6+2*6*12+````+n*3n*6n)^2

[3n(n+1)+n(n+1)(2n+1)]/6+n(n+2)化简 Sn=n(n+2)(n+4)的分项等于1/6[n(n+2)(n+4)(n+5)-(n-1)n(n+2)(n+4)]吗? 证明不等式：(1/n)^n+(2/n)^n+(3/n)^n+.+(n/n)^n 已知888个连续正整数之和:n+(n+1)+(n+2)+(n+3)+(n+4)+(n+5)+(n+6)+(n+7)+·· 化简：1/(n+1)(n+2)+1/(n+2)(n+3)+1/(n+3)(n+4) (n+1)(n+2)/1 +(n+2)(n+3)/1 +(n+3)(n+4)/1 如果正整数n使得［n/2]+[n/3]+[n/4]+[n/5]+[n/6]=69,则n= M=(N-1)×1+(N-2)×2+(N-3)×4+(N-4)×8+(N-5)×16+(N-6)×32+(N-7)×64 (2^n+4^n+6^n+8^n)^(1/n)当n趋于无穷时的极限 如果正整数n使得[n/2]+[n/3]+[n/4]+[n/5]+[n/6]=69,则n为（ ）.（[ n ]表示不超过n (1*2*4+2*4*8+`````+n*2n*4n/1*3*6+2*6*12+````+n*3n*6n)^2 16n^a+4n^3+6n^2+7^n=0,求n