01
The problem
Prove or disprove that every row of Kimberling’s triangular-number interspersion array contains infinitely many primes.
The sponsor notes that the claim reaches the difficulty of the Bunyakovsky conjecture for irreducible integer polynomials.
Open since2011sequence-record date
Last checked2026.07.27Catalog verification
02
Reward offers
Offer 01$50Clark Kimberling
Personal offerBe first to publish a solution in a refereed journal, or submit a short proof that Kimberling accepts as correct and complete. For solutions after 1 January 2025, Kimberling says the stated amount will be donated in the solver’s name to the Online Encyclopedia of Integer Sequences; it is not direct cash to the solver.
Current post-2025 form: a donation to OEIS in the solver’s name.