Block #322,979

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 12/21/2013, 8:58:27 AM · Difficulty 10.1971 · 6,491,489 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
e8d6788083628aa087e7f571f1043d5af7812d338977af1c5531d9750a94cf5e

Height

#322,979

Difficulty

10.197090

Transactions

8

Size

4.81 KB

Version

2

Bits

0a32747f

Nonce

29,625

Timestamp

12/21/2013, 8:58:27 AM

Confirmations

6,491,489

Merkle Root

9e937a00f49dfd83d945d2744ee8bfeaa16f4224ea1830f604d0ce65c36adb88
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.

1.028 × 10¹⁰⁶(107-digit number)
10289015138021356478…05091424971936188801
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
1.028 × 10¹⁰⁶(107-digit number)
10289015138021356478…05091424971936188801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
2.057 × 10¹⁰⁶(107-digit number)
20578030276042712957…10182849943872377601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
4.115 × 10¹⁰⁶(107-digit number)
41156060552085425915…20365699887744755201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
8.231 × 10¹⁰⁶(107-digit number)
82312121104170851831…40731399775489510401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
1.646 × 10¹⁰⁷(108-digit number)
16462424220834170366…81462799550979020801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
3.292 × 10¹⁰⁷(108-digit number)
32924848441668340732…62925599101958041601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
6.584 × 10¹⁰⁷(108-digit number)
65849696883336681464…25851198203916083201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
1.316 × 10¹⁰⁸(109-digit number)
13169939376667336292…51702396407832166401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
2.633 × 10¹⁰⁸(109-digit number)
26339878753334672585…03404792815664332801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
5.267 × 10¹⁰⁸(109-digit number)
52679757506669345171…06809585631328665601
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:57,759,817 XPM·at block #6,814,467 · updates every 60s
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