Take each number mod 37 and map it to the following character set: 0-25 is the alphabet (uppercase), 26-35 are the decimal digits, and 36 is an underscore. Wrap your decrypted message in picoCTF.
Just follow the instructions, really.
from string import ascii_uppercase, digitsnumbers = [165,248,94,346,299,73,198,221,313,137,205,87,336,110,186,69,223,213,216,216,177,138]alphabet = ascii_uppercase + digits +'_'flag =''for n in numbers: flag += alphabet[n %37]print(flag)# picoCTF{R0UND_N_R0UND_B6B25531}