(1)结论就是n(n+1)(n+2)(n+3)+1=[n(n+3)+1]²证明过程就是n(n+1)(n+2)(n+3)+1和[n(n+3)+1]²的展开式结果都是n^4+6n^3+11n^2+6n+1(2)20000×20001×20002×20003+1=（ 4000600001的平方）...