XPM Prime Explorer symbol
XPMPrime Explorer

Block #915,255

1CCLength 11β˜…β˜…β˜…β˜†β˜†

Cunningham Chain of the First Kind Β· Discovered 1/30/2015, 12:18:10 AM Β· Difficulty 10.9262 Β· 5,893,504 confirmations

1CC
Cunningham Chain of the First Kind

A sequence where each prime is double the previous prime plus one.

Block Header
Block Hash
a9d4bd27e72fa74f438ebd72e51eb9c3436c3db61319401b7800adc052231c50
View on Chainz β†—

Height

#915,255

Difficulty

10.926151

Transactions

2

Size

7.94 KB

Version

2

Bits

0aed183e

Nonce

178,808,128

Timestamp

1/30/2015, 12:18:10 AM

Confirmations

5,893,504

Mined by

⛏️ P2SHANSXnLY2HX2a5e6fdcDUZDtfwTSd25TjkD

Merkle Root

91639e28156f1ee3b3c2c5ccd4bdd8e4715f2438cf0a03fee3740eabc3078bc9
Transactions (2)
Coinbasebdf175e061c7cb…86fc4fa9fb3caf
1 in β†’ 1 out8.4600 XPM116 B
ANSXnLY2…Sd25TjkD
98e36e11d4c461…b0b22c529e43ea
53 in β†’ 2 out3104.4757 XPM7.74 KB
APa9VWcA…5QipwGTqAHSYuthm…8ZKze41E
Prime Chain Origin

This is the prime chain origin stored in the block header. It is a composite number (not prime itself) β€” it equals the first prime in the chain multiplied by a primorial. The origin anchors the entire chain to this specific block.

8.592 Γ— 10⁹⁢(97-digit number)
85924188178456568210…26958953475592698719
Discovered Prime Numbers
p_k = 2^k Γ— origin βˆ’ 1

These are the actual prime numbers discovered by this block, computed using the verified Primecoin formula. Each number has been independently confirmed to pass the Fermat primality test. Use the FactorDB links to verify any number independently.

1
origin βˆ’ 1
8.592 Γ— 10⁹⁢(97-digit number)
85924188178456568210…26958953475592698719
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2+1 β†’
2
2^1 Γ— origin βˆ’ 1
1.718 Γ— 10⁹⁷(98-digit number)
17184837635691313642…53917906951185397439
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2+1 β†’
3
2^2 Γ— origin βˆ’ 1
3.436 Γ— 10⁹⁷(98-digit number)
34369675271382627284…07835813902370794879
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2+1 β†’
4
2^3 Γ— origin βˆ’ 1
6.873 Γ— 10⁹⁷(98-digit number)
68739350542765254568…15671627804741589759
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2+1 β†’
5
2^4 Γ— origin βˆ’ 1
1.374 Γ— 10⁹⁸(99-digit number)
13747870108553050913…31343255609483179519
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2+1 β†’
6
2^5 Γ— origin βˆ’ 1
2.749 Γ— 10⁹⁸(99-digit number)
27495740217106101827…62686511218966359039
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2+1 β†’
7
2^6 Γ— origin βˆ’ 1
5.499 Γ— 10⁹⁸(99-digit number)
54991480434212203654…25373022437932718079
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2+1 β†’
8
2^7 Γ— origin βˆ’ 1
1.099 Γ— 10⁹⁹(100-digit number)
10998296086842440730…50746044875865436159
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2+1 β†’
9
2^8 Γ— origin βˆ’ 1
2.199 Γ— 10⁹⁹(100-digit number)
21996592173684881461…01492089751730872319
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2+1 β†’
10
2^9 Γ— origin βˆ’ 1
4.399 Γ— 10⁹⁹(100-digit number)
43993184347369762923…02984179503461744639
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2+1 β†’
11
2^10 Γ— origin βˆ’ 1
8.798 Γ— 10⁹⁹(100-digit number)
87986368694739525847…05968359006923489279
Verify on FactorDB β†—Wolfram Alpha β†—

What this block proved

The miner who found this block proved the existence of 11 consecutive prime numbers forming a Cunningham Chain of the First Kind. The prime chain origin β€” the large number shown above β€” anchors the chain and is divisible by a primorial (the product of small primes), cryptographically tying these prime numbers to this specific block.

β˜…β˜…β˜…β˜†β˜†
Rarity
RareChain length 11

Approximately 1 in 1,000 blocks. Noteworthy discoveries.

How Primecoin's Proof-of-Work Constructs These Primes

Primecoin stores a value called the prime chain origin in each block. The miner found a large integer such that when divided by a primorial (the product of small primes: 2 Γ— 3 Γ— 5 Γ— 7 Γ— …), the result is the first prime in the chain. The origin is deliberately divisible by this primorial β€” that divisibility is part of the proof.

Prime Chain Origin = First Prime Γ— Primorial (2Β·3Β·5Β·7Β·11·…)
Source: Primecoin prime.cpp β€” CheckPrimeProofOfWork()

This is why the origin has many small prime factors β€” those factors are the primorial divisor. The chain then extends from the first prime using the 1CC formula:

1CC: p₁ (first prime), pβ‚‚ = 2p₁ + 1, p₃ = 2pβ‚‚ + 1, …
Cross-reference on Chainz Explorer
Circulating Supply:57,714,121 XPMΒ·at block #6,808,758 Β· updates every 60s
xpmprime.info is a work in progress. If you enjoy using this service you can support this project with a Primecoin donation.
AQZeJoQ81VgeHQBpEYTgvNqV1gnz3L5SvK

Cookie Preferences

We use cookies to enhance your experience. Some are essential for the site to function, while others help us understand how you use the site.

Β·Privacy Policy