repunit

plural repunits

1. A repdigit consisting only of one or more occurrences of the digit 1.

   11, 111, and 1,111 are repunits.

   2 more examples

   The only known prime repunits are R2, R19, R23, and more recently R317 (discovered by Williams in 1978) and R1031 (discovered by Williams & Dubner in 1986). Moreover, Dubner has determined that for every other prime p less than 10000, the repunit Rp is composite.

   1991, Paulo Ribenboim, The Little Book of Big Primes, page 172

   In this study is introduced a novel generalization of repunit and one-zero numbers through the formulation of the generalized One-kZero.

   2025 November 20, Paula M. M. C. Catarino, Grieg A. Costa, Eudes A. Costa, “On Generalized One-kZero Numbers”, in Axioms, volume 14, number 11, MDPI, →DOI, →ISSN, page 1