Convert a list of decimal values in a text file into hex format

I have a need to convert a list of decimal values in a text file into hex format, so for example test.txt might contain: 131072 196608 262144 327680 393216 ... the output should be list of hex values (hex 8 digit, with leading zeroes): 00020000 00030000 00040000 ... the output is printed into the text file. How to make this with python or linux shell script? ### EDIT #1 I missed one extra operation: I need to add 80000000 hex to each of the created hex values. (arithmetic addition, to apply to already created list of hex values).