The length-restricted antipalindrome sum conjecture

About 9 years old · traced to

An antipalindrome is a natural number whose canonical base-22 expansion is an antipalindromic word, meaning that the word equals the complement of its reversal. An even integer has an even least significant bit. For an odd integer length n≥9n\geq 9, consider even integers whose canonical base-22 expansions have length nn.

The length-restricted antipalindrome sum conjecture. Every even integer of length nn, for nn odd and n≥9n\geq 9, is the sum of at most 1010 antipalindromes of length n−3n-3.

The conjecture is intended to be proved using nondeterministic pushdown automata, but the authors' computations were incomplete because their program ran out of space. They hoped to establish it as a theorem in a future version; its truth would imply that every even natural number is the sum of at most 1313 antipalindromes.

References

Primary source

Aayush Rajasekaran, Jeffrey Shallit and Tim Smith, “Sums of Palindromes: an Approach via Automata”, arXiv:1706.10206 (2017).

Progress summary

Never refreshed

Nothing recorded yet. Refresh searches the literature and the public web for attempts on this problem, and writes the first summary here.

Solutions 0

No solutions have been posted yet.