igs.py

print("Enter number of elements: ")
n = int(input())
elements, binary_elements = [], []

for i in range(n):
    # Take input and store in array
    x = int(input())
    elements.append(x)

    # Convert to binary array of 8 bits
    binary_elements.append('{0:08b}'.format(x))

sum = '00000000'
print("Number\tGray Level\tSum\t\tIGS Code")
for i in range(n):
    if binary_elements[i][:4] == '1111':
        # Add 0000 => don't add anything
        sum = binary_elements[i]
    else:
        # Add 4 bits of LSB of sum to input
        sum = '{0:08b}'.format(int(sum[4:],2) + elements[i])

    print("%d\t%s\t%s\t%s" % (elements[i], binary_elements[i], sum, sum[:4]))

Output: