7^491-1

Open composite · C387

NFS Planning

GNFS Murphy estimate: 7.99e-26
SNFS Murphy score: 7.28e-19
Preferred method: SNFS
SNFS possible: Yes
SNFS degree: 7
SNFS skew: 1.03496

Identifiers

Target expression: 7^491-1
Target link: FactorDB page
Target ID: 1000000000018628959
Target changed: -
Parent query: Same as target
Parent ID: -
Cofactor token: C387
Imported: Jun 03, 2026, 04:31 PM UTC

Raw pmain126 Factorization

(1) 983.696239.6644251020606657127. C387

SNFS Polynomial

Polynomial

Degree: 7
Murphy: 7.28e-19
Skew: 1.03496
Selected: Best

n: 321535182299637154328168138829462205181230874550744363777171438812599768071665148668547220346421953092484461361227318015612180761617948016482258494760010318773883295420389135047813866158859216721438800787212045801489154869315059135599535036244004265824050214998846508292666820460814231919703894610479029773046436139278072279807695955982778874790164149772580530702955426746445808796207543
# 7^491-1, difficulty: 414.94, skewness: 1.32
# cost: 3.76355e+23, est. time: 179216568.21 GHz days (not accurate yet!)
# Optimized skew: 1.03496 Murphy: 7.28e-19
skew: 1.03496
c7: 1
c0: -7
Y1: -143503601609868434285603076356671071740077383739246066639249
Y0: 1
type: snfs