Write a Python program that accepts an integer (n) and computes the value of n+nn+nnn.

Sure, here is a simple Python program that does what you asked for:

# Accepts an integer from user
n = int(input("Enter an integer: "))

# Computes the value of n+nn+nnn
nn = int(str(n) * 2)
nnn = int(str(n) * 3)

# Adds n, nn, and nnn
result = n + nn + nnn

# Prints the result
print("The result is:", result)

Here's how it works:

1. The input() function is used to take an integer input from the user.
2. The str() function is used to convert the integer to a string so that it can be repeated using the * operator.
3. The int() function is used to convert the repeated string back to an integer.
4. The + operator is used to add the integers together.
5. The print() function is used to display the result.