Block #339,814

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 1/2/2014, 8:45:02 AM · Difficulty 10.1308 · 6,466,447 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
6d61e83e4b5b37d8b414222785baf5678d5e7db5b0e9a8b26ed654bfbfcbca78

Height

#339,814

Difficulty

10.130765

Transactions

1

Size

1.05 KB

Version

2

Bits

0a2179cd

Nonce

203,449

Timestamp

1/2/2014, 8:45:02 AM

Confirmations

6,466,447

Merkle Root

579ab615d9281a24115c1ce6e747b9964ef228e910cf07c26ef2a70121d0f1cb
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.

5.166 × 10¹⁰⁰(101-digit number)
51664574904360591897…86355547452297502721
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
5.166 × 10¹⁰⁰(101-digit number)
51664574904360591897…86355547452297502721
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
1.033 × 10¹⁰¹(102-digit number)
10332914980872118379…72711094904595005441
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
2.066 × 10¹⁰¹(102-digit number)
20665829961744236759…45422189809190010881
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
4.133 × 10¹⁰¹(102-digit number)
41331659923488473518…90844379618380021761
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
8.266 × 10¹⁰¹(102-digit number)
82663319846976947036…81688759236760043521
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
1.653 × 10¹⁰²(103-digit number)
16532663969395389407…63377518473520087041
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
3.306 × 10¹⁰²(103-digit number)
33065327938790778814…26755036947040174081
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
6.613 × 10¹⁰²(103-digit number)
66130655877581557629…53510073894080348161
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
1.322 × 10¹⁰³(104-digit number)
13226131175516311525…07020147788160696321
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
2.645 × 10¹⁰³(104-digit number)
26452262351032623051…14040295576321392641
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:57,694,172 XPM·at block #6,806,260 · updates every 60s
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