1 142 263 Exponent Status

PrimeNet Exponent Status

M_n

Status

Details

Composite: proven not-prime with both PRP and Lucas-Lehmer tests

No factors below 2⁶⁹

TF target 2⁶⁰

TF below 2^81 is very unlikely to find new factors due to ECM effort.

P-1

B1 =	12000000
B2 =	88140272220

ECM

Digits	B1	Curves
25	50000	280 / 280
30	250000	111 / 640

Estimated T-Level: 25.9 ⓘ

Status	Date	User	Residue	Shift
Verified		David Slowinski	1CD4	0
Verified		Jeff Woods	1F38AB312A7C7CD4	0
Verified	2002-06-29	S57483	1F38AB312A7C7CD4	263143
Verified	2016-06-01	MadPoo	1F38AB312A7C7CD4	964018

Status	Date	User	Residue	Shift	Type	Base
Verified	2020-11-05	Ethan O'Connor	9191A44DC4DCE964	86987	1	3
Verified	2025-09-01	Kriesel	9191A44DC4DCE964	0	1	3

History

Date	User	Type	Result
2025-09-02	Resolver	CERT	PRP Certification CERT proof power = 6 Proof certified good
2025-09-01	Kriesel	C-PRP	9191A44DC4DCE964 PRP proof power = 6 PRP: Verified Proof certified good
2022-05-24	mikr	NF-PM1	B1=12000000, B2=88140272220
2021-07-23	MadPoo	NF	no factor from 2^68 to 2^69
2020-11-05	rucio	CERT	PRP Certification CERT proof power = 6 Proof certified good
2020-11-05	Ethan O'Connor	C-PRP	9191A44DC4DCE964 PRP proof power = 6 PRP: Verified Proof certified good
2018-11-13	Joss	NF-PM1	B1=1142263, B2=137071560, E=12
2018-07-08	ramgeis	NF	no factor from 2^67 to 2^68
2018-04-16	Joss	NF-PM1	B1=1142263, B2=114226300, E=12
2018-04-13	Joss	NF-PM1	B1=543200
2017-02-16	Smok_bmv	NF	no factor from 2^66 to 2^67
2016-07-27	Bruno Victal	NF-PM1	B1=2500000, B2=62500000, E=12
2016-07-25	Bruno Victal	NF-PM1	B1=2500000, B2=62500000, E=12
2016-06-01	MadPoo	C-LL	1F38AB312A7C7CD4
2016-02-23	Mark Rose	NF	no factor from 2^58 to 2^60
2015-07-18	omylist	NF	no factor from 2^65 to 2^66
2015-01-12	lycorn	NF	no factor from 2^64 to 2^65
2014-12-28	Matthias Wurtinger	NF	no factor from 2^63 to 2^64
2012-10-21	dbaugh	NF	no factor from 2^62 to 2^63
2012-08-27	Axelsson	NF	no factor from 2^61 to 2^62
2009-03-08	Sturle Sunde	NF	no factor from 2^60 to 2^61

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