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.