Alternating letters and numbers. Regex will help you find the keyword
Not sure if I have the right method but here is how I got it:
Make pairs
3n 2x 2a 2f 2e 3c 3d 2s 3f 2o 3h 2w 3j 2s 2e 2d 2g 3d 2p
The keyword section logically his 3c 3d 2s 3f 2o 3h 2w 3j 2s. Using the Regex string ^..(.).....\1$ reveal that the only possible keyword is operative.
The decimal values to get OPERATIVE are 79 80 69 82 65 84 73 86 69. The formula to get these numbers is (n*26)+(l-1) where n is number and l is letter using a=0