Block #441,608

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 3/13/2014, 7:31:12 AM · Difficulty 10.3485 · 6,366,188 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
bb493a81f86ca9b8ef3818da432a54e0cca1ea69948bfeeb092e74ddf251a6be

Height

#441,608

Difficulty

10.348470

Transactions

1

Size

970 B

Version

2

Bits

0a593559

Nonce

173,595

Timestamp

3/13/2014, 7:31:12 AM

Confirmations

6,366,188

Merkle Root

4e2c25cbb0e7a3f46738a16efe21775d96714b27245fa82bbafbe6912ae4b23d
Prime Chain Origin

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

1.075 × 10⁹⁷(98-digit number)
10754973861161109776…48206513968422205441
Discovered Prime Numbers
p_k = 2^k × origin + 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 + 1
1.075 × 10⁹⁷(98-digit number)
10754973861161109776…48206513968422205441
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
2.150 × 10⁹⁷(98-digit number)
21509947722322219553…96413027936844410881
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
4.301 × 10⁹⁷(98-digit number)
43019895444644439106…92826055873688821761
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
8.603 × 10⁹⁷(98-digit number)
86039790889288878212…85652111747377643521
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
1.720 × 10⁹⁸(99-digit number)
17207958177857775642…71304223494755287041
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
3.441 × 10⁹⁸(99-digit number)
34415916355715551285…42608446989510574081
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
6.883 × 10⁹⁸(99-digit number)
68831832711431102570…85216893979021148161
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
1.376 × 10⁹⁹(100-digit number)
13766366542286220514…70433787958042296321
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
2.753 × 10⁹⁹(100-digit number)
27532733084572441028…40867575916084592641
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
5.506 × 10⁹⁹(100-digit number)
55065466169144882056…81735151832169185281
Verify on FactorDB ↗Wolfram Alpha ↗

What this block proved

The miner who found this block proved the existence of 10 consecutive prime numbers forming a Cunningham Chain of the Second Kind. The prime chain origin — the large number shown above — anchors the chain and is divisible by a primorial (the product of small primes), cryptographically tying these prime numbers to this specific block.

★★☆☆☆
Rarity
UncommonChain length 10

Roughly 1 in 100 blocks. Solid but expected in a healthy network.

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 × 3 × 5 × 7 × …), the result is the first prime in the chain. The origin is deliberately divisible by this primorial — that divisibility is part of the proof.

Prime Chain Origin = First Prime × Primorial (2·3·5·7·11·…)
Source: Primecoin prime.cpp — CheckPrimeProofOfWork()

This is why the origin has many small prime factors — those factors are the primorial divisor. The chain then extends from the first prime using the 2CC formula:

2CC: p₁ (first prime), p₂ = 2p₁ − 1, p₃ = 2p₂ − 1, …
Circulating Supply:57,706,401 XPM·at block #6,807,795 · updates every 60s
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