==> arithmetic/arithmetic.progression.s <== There is an arithmetic progression of 21 primes: 142072321123 + 1419763024680 i, 0 <= i < 21. It was discovered on 30 November 1990, by programs running in the background on a network of Sun 3 workstations in the Department of Computer Science, University of Queensland, Australia. See: Andrew Moran and Paul Pritchard, The design of a background job on a local area network, Procs. 14th Australian Computer Science Conference, 1991, to appear.