plateau prime
(another Prime Pages' Glossary entries)
The Prime Glossary
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GIMPS has discovered a new largest known prime number: 282589933-1 (24,862,048 digits)

A plateau prime is a palindromic prime having all equal internal digits and smaller matching end digits. E.g., 181, 1777771, 355555553, and 5(10141-1)/9 - 2(10140+1).

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