Minimal first occurrence of each row-count value

Determine whether, for every integer v≥2, the least positive integer N such that N belongs to exactly v rows R_m={⌊kφ^m⌋:k≥1} is the Lucas number L_{4v−5}.

Background

The paper defines R_m={⌊kφm⌋:k≥1} and a(N)=#m≥1:N∈R_m, the number of rows of Kimberling’s array containing N. The authors prove that every positive integer v occurs infinitely often as a value of a(N), and that each level set {N:a(N)=v} has positive natural density.

Proposition 4.1 establishes that a(L_m)=(m+1)/4+1 for odd m≥3, implying a(L_{4v−5})=v for every v≥2. The unresolved issue is whether these explicitly identified Lucas numbers are not merely examples with row count v, but are the smallest such examples. Computations through N≤108 verify the claim for v≤10.

References

The data also suggest the following, which we leave open. For every $v\ge2$, the least $N$ with $a(N)=v$ is $L_{4v-5}$.

— On three conjectures of Kimberling concerning the array $\lfloor k\varphi^n\rfloor$  (2610.05776 - Ashburn, 5 Oct 2026) in Section 5, “Densities, computations and an open question,” immediately after Proposition 5.1