Need first output to be a number, but its that numbers concatenation

My code is as follows:

import java.util.Scanner;

public class QuestionOne

{

public static void main(String[]args)

 {
int numberofDays;

int sharePoints;

Scanner keyboard = new Scanner (System.in);

System.out.print("Number of days in the period: ");

numberofDays = keyboard.nextInt();

System.out.print("Share points on the first day: ");

sharePoints = keyboard.nextInt();

while (numberofDays < 10 || numberofDays > 20)

{

  System.out.println("The number of days doesn’t meet the required criteria, enter it again");

  System.out.print("Number of days in the period: ");

  numberofDays = keyboard.nextInt();

}

System.out.println("Day " + " Share Points");

for(int i = 1; i <= numberofDays; i++)

{

  if(numberofDays % 2 == 0)


    if(i <= numberofDays/2)

  {

    sharePoints = sharePoints + 50;

    System.out.println(i + "    " + sharePoints);
  }

  else

  {

    sharePoints = sharePoints - 25;

    System.out.println(i + "    " + sharePoints);

  }

  else

  {

    if(i <= numberofDays/2 + 1)

    {

      sharePoints = sharePoints + 50;

      System.out.println(i + "    " + sharePoints);

    }

    else

    {

      sharePoints = sharePoints - 25;

      System.out.println(i + "    " + sharePoints);

    }

  }

}

}
}

This code should output to something like (as an example if the user were to enter the values 11 for the day and 550 for share price):

Day Share Points
1 550
2 600
3 650
4 700
5 750
6 800
7 775
8 750
9 725
10 700
11 675

however when I enter 11 for the day, and 550 for the share price, my code looks like:

Day Share Points
1 600
2 650
3 700
4 750
5 800
6 850
7 825
8 800
9 775
10 750
11 725

From what I can tell according to my code, I have coded it so that it adds 50 every time until the number six- whereas I want it to display the first number as the user enters it in, then to start adding and subtracting accordingly (note that everything is as I want it in my output except for the first number, and the proceeding numbers, as a result, being different). My wording may not be very accurate, but I hope the example outputs are enough to explain what I want as my output.