Block #379,284

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 1/28/2014, 10:47:13 AM · Difficulty 10.4155 · 6,413,700 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
b6d9c3dcf233e3ce4473906fb6571803c86910a506c332b72b70101072b9db82

Height

#379,284

Difficulty

10.415513

Transactions

2

Size

1.20 KB

Version

2

Bits

0a6a5f0b

Nonce

614

Timestamp

1/28/2014, 10:47:13 AM

Confirmations

6,413,700

Merkle Root

1a4c9976dfa862895c71f549d7d8311c32b10f9f98d494183de768d04cda94cb
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.

1.879 × 10⁹⁸(99-digit number)
18790376933143645962…49131291543166214721
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
1.879 × 10⁹⁸(99-digit number)
18790376933143645962…49131291543166214721
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
3.758 × 10⁹⁸(99-digit number)
37580753866287291924…98262583086332429441
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
7.516 × 10⁹⁸(99-digit number)
75161507732574583848…96525166172664858881
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
1.503 × 10⁹⁹(100-digit number)
15032301546514916769…93050332345329717761
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
3.006 × 10⁹⁹(100-digit number)
30064603093029833539…86100664690659435521
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
6.012 × 10⁹⁹(100-digit number)
60129206186059667079…72201329381318871041
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
1.202 × 10¹⁰⁰(101-digit number)
12025841237211933415…44402658762637742081
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
2.405 × 10¹⁰⁰(101-digit number)
24051682474423866831…88805317525275484161
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
4.810 × 10¹⁰⁰(101-digit number)
48103364948847733663…77610635050550968321
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
9.620 × 10¹⁰⁰(101-digit number)
96206729897695467326…55221270101101936641
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:57,587,854 XPM·at block #6,792,983 · updates every 60s
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