As mentioned previously, the Encyclopedia of Integer Sequences is 50 this year. To celebrate that fact, and to encourage readers to concentrate on filling in the gaps in the missing entries instead of just adding new ones, there’s a \$1,000 prize for the best solution to an open problem posed in an OEIS entry.
The announcement by OEIS creator Neil Sloane seems only to have been published as a PDF, so I’m reproducing it here for everyone’s convenience: