In modern number theory, newly defined sequences often find use in cryptography. If we define as those that are both pseudoprime to base 2 and non-palindromic but become palindromic after reversing digits and multiplying by the original number’s digit sum, they could serve as keys in hash functions.
Thus solutions require small ( L ).
In the early 2000s, puzzle designers on forums like StackExchange Puzzling and the now-defunct "Numberphile Community" revived the Badulla Badu idea. They proposed using Badu pair cycles as a simple checksum or proof-of-work for lightweight devices. Badulla Badu Numbers--------
Let: