  The recent history of The On-Line Encyclopedia of Integer Sequences (or
OEIS), describing developments since 2009, and discussing recent sequences
involving interesting unsolved problems and in many cases spectacular
illustrations. These include: Peaceable Queens, circles in the plane, the
earliest cube-free binary sequence, the EKG and Yellowstone permutations, other
lexicographically earliest sequences, iteration of number-theoretic functions,
home primes and power trains, a memorable prime, a missing prime, Post's tag
system, and coordination sequences.
