Gregory–Newton summation identity for signed pancake distances

Let RkB(n)R_k^B(n) denote the number of signed permutations of size nn whose burnt-pancake distance from the sorted stack is kk. Summation identity conjecture. If k,n1k,n\geq1, then

RkB(n)=j=1k(i=0kj(1)i(i+j1i)(ni+j))RkB(j).R_k^B(n)=\sum_{j=1}^k\left(\sum_{i=0}^{k-j}(-1)^i\binom{i+j-1}{i}\binom{n}{i+j}\right)R_k^B(j).

The identity is observed in the source and is motivated by the assertion that the functions RkB(n)R_k^B(n) are integer-valued polynomials together with the Gregory–Newton interpolation formula. No proof or resolution is supplied, so it remains open.

Sources & referencesView supporting material

Primary source

Saúl A. Blanco, Charles Buehrle and Akshay Patidar, “On the number of pancake stacks requiring four flips to be sorted”, arXiv:1902.04055 (2019).

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.