Block #480,744

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 4/8/2014, 11:50:03 AM · Difficulty 10.5222 · 6,346,141 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
75ac4401cba574a3e6734e275b3cbf79e99289a571bca9fd9f6af7dbaec471aa

Height

#480,744

Difficulty

10.522203

Transactions

6

Size

4.63 KB

Version

2

Bits

0a85af14

Nonce

4,491

Timestamp

4/8/2014, 11:50:03 AM

Confirmations

6,346,141

Merkle Root

069e892d0a41bd16116cf18efb8d0555a075df43c2916f8858e8421491e7afc5
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.

1.402 × 10¹⁰¹(102-digit number)
14022035635607804389…80719856627329408001
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
1.402 × 10¹⁰¹(102-digit number)
14022035635607804389…80719856627329408001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
2.804 × 10¹⁰¹(102-digit number)
28044071271215608779…61439713254658816001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
5.608 × 10¹⁰¹(102-digit number)
56088142542431217558…22879426509317632001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
1.121 × 10¹⁰²(103-digit number)
11217628508486243511…45758853018635264001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
2.243 × 10¹⁰²(103-digit number)
22435257016972487023…91517706037270528001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
4.487 × 10¹⁰²(103-digit number)
44870514033944974046…83035412074541056001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
8.974 × 10¹⁰²(103-digit number)
89741028067889948093…66070824149082112001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
1.794 × 10¹⁰³(104-digit number)
17948205613577989618…32141648298164224001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
3.589 × 10¹⁰³(104-digit number)
35896411227155979237…64283296596328448001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
7.179 × 10¹⁰³(104-digit number)
71792822454311958474…28566593192656896001
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:57,859,245 XPM·at block #6,826,884 · updates every 60s
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