Block #322,637

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 12/21/2013, 3:27:31 AM · Difficulty 10.1949 · 6,495,367 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
376a22dd27e1aa43a706601202215f91094cc554b6b7e81dfe6253cd2f1ebdc0

Height

#322,637

Difficulty

10.194856

Transactions

29

Size

11.93 KB

Version

2

Bits

0a31e219

Nonce

96,400

Timestamp

12/21/2013, 3:27:31 AM

Confirmations

6,495,367

Merkle Root

34a77f1024fd25decbe72ef4ce2c239e231b4ae95cdabd6c7ef168ba9f0ce01b
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.

7.260 × 10⁹⁴(95-digit number)
72602424162343872618…13519711154766748001
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
7.260 × 10⁹⁴(95-digit number)
72602424162343872618…13519711154766748001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
1.452 × 10⁹⁵(96-digit number)
14520484832468774523…27039422309533496001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
2.904 × 10⁹⁵(96-digit number)
29040969664937549047…54078844619066992001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
5.808 × 10⁹⁵(96-digit number)
58081939329875098094…08157689238133984001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
1.161 × 10⁹⁶(97-digit number)
11616387865975019618…16315378476267968001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
2.323 × 10⁹⁶(97-digit number)
23232775731950039237…32630756952535936001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
4.646 × 10⁹⁶(97-digit number)
46465551463900078475…65261513905071872001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
9.293 × 10⁹⁶(97-digit number)
92931102927800156951…30523027810143744001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
1.858 × 10⁹⁷(98-digit number)
18586220585560031390…61046055620287488001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
3.717 × 10⁹⁷(98-digit number)
37172441171120062780…22092111240574976001
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:57,788,097 XPM·at block #6,818,003 · updates every 60s
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