Conjectures associated with A100800

formal-conjectures · oeis · ams-11

Let $f(n) = n + \text{sum of the digits of } n$. If $f(n)$ is multiple of $n$ then $a(n)= f(n)$
else $a(n) = f(f(f(n)))\dots$ until one gets a multiple of $n$; $a(n) = 0$ if no such number
exists.

A100800 Conjecture: No term is zero.

Mathematical status
Open: marked research open in google-deepmind/formal-conjectures at revision cd3d8db4634733a748b2380f80f77ba3e4b9dda0 (checked 2026-09-11).

Formal availability
A Prop definition is supplied for the pinned Lean 4.33.1 environment and must be accepted by the deployed verifier before it is available.

Sources and provenance
Upstream reference cited by formal-conjectures (checked 2026-09-11): https://oeis.org/A100800
Formal statement provenance (Apache-2.0) (checked 2026-09-11): https://github.com/google-deepmind/formal-conjectures/blob/cd3d8db4634733a748b2380f80f77ba3e4b9dda0/FormalConjectures/OEIS/100800.lean
Local target: Corpus.OEIS100800.conjecture
Source SHA-256: f7faf84db12805f9d5dc299dcee1799cd2373ebc712c778f6623b7bed8eb4e9b
Lean v4.33.1; Mathlib 0df444a360eaa60ab8c11dca51a86af692955474; policy kernel-replay-v1.
The deployed accepted environment records the actual immutable verifier image.

Research discussions are not verified proofs. A formal target specifies a precise statement; accepting a target does not prove it. Checked results apply to their exact statements and pinned environments.

Public JSON record