Block #337,988

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 1/1/2014, 2:50:09 AM · Difficulty 10.1244 · 6,470,308 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
ed40cf177310e69db23b15d3dc6640466f72b1d184ef0c6428c33e3c0e577cac

Height

#337,988

Difficulty

10.124424

Transactions

2

Size

1.45 KB

Version

2

Bits

0a1fda48

Nonce

183,201

Timestamp

1/1/2014, 2:50:09 AM

Confirmations

6,470,308

Merkle Root

6f69928e0c9f008e690378fed61f1b02b4883f0608eef207dcd365ef743067d5
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.

1.313 × 10⁹⁰(91-digit number)
13135467828980298200…83753513112299654301
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
1.313 × 10⁹⁰(91-digit number)
13135467828980298200…83753513112299654301
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
2.627 × 10⁹⁰(91-digit number)
26270935657960596401…67507026224599308601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
5.254 × 10⁹⁰(91-digit number)
52541871315921192802…35014052449198617201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
1.050 × 10⁹¹(92-digit number)
10508374263184238560…70028104898397234401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
2.101 × 10⁹¹(92-digit number)
21016748526368477121…40056209796794468801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
4.203 × 10⁹¹(92-digit number)
42033497052736954242…80112419593588937601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
8.406 × 10⁹¹(92-digit number)
84066994105473908484…60224839187177875201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
1.681 × 10⁹²(93-digit number)
16813398821094781696…20449678374355750401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
3.362 × 10⁹²(93-digit number)
33626797642189563393…40899356748711500801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
6.725 × 10⁹²(93-digit number)
67253595284379126787…81798713497423001601
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:57,710,421 XPM·at block #6,808,295 · updates every 60s
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