문제는 다음과 같습니다.

https://www.acmicpc.net/step/3

　
import java.util.Scanner;

public class ForTestMain {
    public static void main(String[] args) {
    	Scanner sc = new Scanner(System.in);
    	int a = sc.nextInt();
        
    	System.out.println("2739=======================");
    	for(int i=1; i<=9; i++){ //2739번
    		System.out.println(a+" * "+i+ " = "+ a*i);
    	}
        
    	System.out.println("2741=======================");
    	for(int i=1; i<=a; i++){ //2741번
    		System.out.println(i);
    	}
        
    	/*System.out.println("2742=======================");
    	for(int i=a; a>=1; a--){ //2742번, a값이 변해서 주석처리했습니다.
    		System.out.println(a);
    	}*/
        
    	System.out.println("2438=======================");
    	for(int i=1; i<=a; i++){ //2438번
    		for(int j=1; j<=i; j++){
    			System.out.print("*");
    		}
            System.out.println();
    	}
        
    	System.out.println("2439=======================");
    	for(int i=1; i<=a; i++){ //2439번
    		for(int j=a-i; j>0; j--){
    			System.out.print(" ");
    		}
    		for(int k=i; k>0; k--){
    			System.out.print("*");
    		}
    		System.out.println();
    	}
        
    	System.out.println("2440=======================");
    	for(int i=a; i>=1; i--){ //2440번
    		for(int j=1; j<=i; j++){
    			System.out.print("*");
    		}
            System.out.println();
    	}
        
    	System.out.println("2441=======================");
    	for(int i=0; i<a; i++){
    		for(int j=a-i; j<a; j++){
    			System.out.print(" ");
    		}
    		for(int k=a-i; k>0; k--){
    			System.out.print("*");
    		}
    		System.out.println();
    	}
        
    }       
}

결과는 아래와 같습니다.