Block #359,827

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 1/15/2014, 1:33:14 AM · Difficulty 10.3877 · 6,442,693 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
16935c8c7cf31cc74a7423d333e3877ddb70f84aa2b4c595ff04d2b902af161a

Height

#359,827

Difficulty

10.387686

Transactions

5

Size

1.37 KB

Version

2

Bits

0a633f61

Nonce

5,617

Timestamp

1/15/2014, 1:33:14 AM

Confirmations

6,442,693

Merkle Root

da964a9f668df204ae3bb31b07e14057eaba7fb5df5f91dd24b61cc6e168fddd
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.

1.104 × 10⁹⁷(98-digit number)
11044408295182273628…13487981582216192001
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
1.104 × 10⁹⁷(98-digit number)
11044408295182273628…13487981582216192001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
2.208 × 10⁹⁷(98-digit number)
22088816590364547257…26975963164432384001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
4.417 × 10⁹⁷(98-digit number)
44177633180729094514…53951926328864768001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
8.835 × 10⁹⁷(98-digit number)
88355266361458189029…07903852657729536001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
1.767 × 10⁹⁸(99-digit number)
17671053272291637805…15807705315459072001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
3.534 × 10⁹⁸(99-digit number)
35342106544583275611…31615410630918144001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
7.068 × 10⁹⁸(99-digit number)
70684213089166551223…63230821261836288001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
1.413 × 10⁹⁹(100-digit number)
14136842617833310244…26461642523672576001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
2.827 × 10⁹⁹(100-digit number)
28273685235666620489…52923285047345152001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
5.654 × 10⁹⁹(100-digit number)
56547370471333240978…05846570094690304001
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:57,664,170 XPM·at block #6,802,519 · updates every 60s
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