$a(n)$ is the integer whose decimal digits are the first $n+1$ decimal digits of $\pi$

formal-conjectures · oeis · ams-11

Wolfgang Haken (1977) conjectured that no term of this sequence is a perfect square,
and estimated the probability that this conjecture is false to be smaller than $10^-9$.

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/A011545
Formal statement provenance (Apache-2.0) (checked 2026-09-11): https://github.com/google-deepmind/formal-conjectures/blob/cd3d8db4634733a748b2380f80f77ba3e4b9dda0/FormalConjectures/OEIS/11545.lean
Local target: Corpus.OEIS11545.conjecture1
Source SHA-256: 70da18617887bdba45888600ad0c5601cc693fb3694c8f17301b684f78f56567
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