1,4,7,10,.,1000的規(guī)律是3*n+1,(n=0,1,2,3...333)
1,11,21,31.1001的規(guī)律是10*m+1,(m=0,1,2,3...100)
相同的數(shù)字則3*n+1=10*m+1,即m=3*n/10,(m,n都是整數(shù))
因此,只有當(dāng)n=10,20,30,.,300,310,320,330時(shí),m=3*n/10才能是整數(shù)
那么在n=10,20,30,.,300,310,320,330間共有33個(gè)數(shù)
答案就是33個(gè)