Block #522,748

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 5/3/2014, 5:29:42 AM · Difficulty 10.8684 · 6,271,983 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
b7c336b65e65a64947047e97cf4457e530589e079378ddc0b866ce92523be25f

Height

#522,748

Difficulty

10.868357

Transactions

10

Size

2.45 KB

Version

2

Bits

0ade4ca8

Nonce

149,674

Timestamp

5/3/2014, 5:29:42 AM

Confirmations

6,271,983

Merkle Root

b7c3d164b529b155cc3eb3f5a77b8e478299235a9dab6f934792017a1a32c827
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.

1.441 × 10⁹⁹(100-digit number)
14413700118649563306…24840148649580357121
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
1.441 × 10⁹⁹(100-digit number)
14413700118649563306…24840148649580357121
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
2.882 × 10⁹⁹(100-digit number)
28827400237299126612…49680297299160714241
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
5.765 × 10⁹⁹(100-digit number)
57654800474598253224…99360594598321428481
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
1.153 × 10¹⁰⁰(101-digit number)
11530960094919650644…98721189196642856961
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
2.306 × 10¹⁰⁰(101-digit number)
23061920189839301289…97442378393285713921
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
4.612 × 10¹⁰⁰(101-digit number)
46123840379678602579…94884756786571427841
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
9.224 × 10¹⁰⁰(101-digit number)
92247680759357205159…89769513573142855681
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
1.844 × 10¹⁰¹(102-digit number)
18449536151871441031…79539027146285711361
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
3.689 × 10¹⁰¹(102-digit number)
36899072303742882063…59078054292571422721
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
7.379 × 10¹⁰¹(102-digit number)
73798144607485764127…18156108585142845441
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:57,601,898 XPM·at block #6,794,730 · updates every 60s
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