PrimeGrid 27121 Prime Search

Purpose

Searching for primes of the forms 27•2ⁿ±1 and 121•2ⁿ±1.

The project ended in 2022 after all n≤10000000 were completed.

Status

• PRPnet status
• Riesel prime 2 27
• Proth prime 2 27
• Riesel prime 2 121
• Proth prime 2 121

History

• 2022-03-21: For 27•2ⁿ±1 all n≤10000000 were checked
• 2021-04-08: For 121•2ⁿ±1 all n≤10000000 were checked
• 2009-02-13: Collaborating work with 12121 Search

See also

• PrimeGrid
• Seventeen or Bust
• Sierpiński problem

External links

• 27121 Prime Search - PrimeGrid forums

PrimeGrid

Miscellaneous

Main

Subprojects

Type Proth : 321 Prime Search 27121 Prime Search Proth Prime Search Proth Prime Search Extended Proth Mega Prime Search Type Sierpiński : Seventeen or Bust Extended Sierpiński Project Prime Sierpiński Problem Sierpiński base 5 Type Riesel : The Riesel Problem Riesel base 5 Type Fermat : Generalized Fermat Prime Search b216+1 b217+1 b218+1 b219+1 b220+1 b221+1 b222+1 Fermat Divisor Search Type Cullen/Woodall : Cullen Prime Search Woodall Prime Search Generalized Cullen Prime Search Type Others : AP27 Search Sophie Germain Search Wieferich and Wall-Sun-Sun Prime Search

Completed

GFN b215+1

Others