# Repdigit Numbers in Java

In this section, we will learn what is a repdigit numbers and also create Java programs to check if the given number is a repdigit number or not. The repdigit number program is frequently asked in Java coding interviews and academics.

## Repdigit Number

Repdigit is short for repeated digits. It is an OEIS sequence A010785. A repdigit is an integer N that has the same digits in its representation in base B and they are equal.

The repdigits composed by repeated ones are called rep-units.

### Repdigit Number Example

Suppose, 444 is a number and base are 10 then the number 444 will be a repdigit number. Similarly, if 2000 is a number and given base is 7 then it will be a repdigit number. Because in base 7, the number 2000 can be written as 5555.

First few repdigit numbers are:

0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 11, 22, 33, 44, 55, 66, 77, 88, 99, 111, 222, 333, 444, 555, 666, 777, 888, 999, 1111, 2222, 3333, 4444, 5555, 6666, 7777, 8888, 9999, 11111, 22222, 33333, 44444, 55555, 66666, 77777, 88888, 99999, 111111, 222222, 333333, 444444, 555555, 666666, etc.

## Steps to Find Repdigit Number

• One by one find all the digits of N in base B.
• Compare every digit with its previous digit.
• If any digit is not equal to the previous digit then return false.
• Otherwise return true.

Let's implement the above steps in a Java program.

## Repdigit Number Java Program

In the following program, we have entered a number N and check it is a repdigit number in base (B) or not.

RepdigitNumberExample.java

Output 1:

```Enter the number: 2000
Enter the base: 7
It is a repdigit number.
```

Output 2:

```Enter the number: 5555
Enter the base: 2
It is not a repdigit number.
```

Output 3:

```Enter the number: 66666
Enter the base: 10
It is a repdigit number.
```

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