Block #467,020

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 3/30/2014, 12:33:48 PM · Difficulty 10.4323 · 6,331,826 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
779285fdca009b808f9f791f4def7223a003591eb38f255a3654889bedbdd2fb

Height

#467,020

Difficulty

10.432321

Transactions

2

Size

1.07 KB

Version

2

Bits

0a6eac96

Nonce

271,440

Timestamp

3/30/2014, 12:33:48 PM

Confirmations

6,331,826

Merkle Root

891ba233bc9a15796f5ef1b2a3861d9a8e6e7e4329f68f6981736a6f986ed099
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.

2.834 × 10⁹⁷(98-digit number)
28347999022023946217…34208611166250841991
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
2.834 × 10⁹⁷(98-digit number)
28347999022023946217…34208611166250841991
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
5.669 × 10⁹⁷(98-digit number)
56695998044047892435…68417222332501683981
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
1.133 × 10⁹⁸(99-digit number)
11339199608809578487…36834444665003367961
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
2.267 × 10⁹⁸(99-digit number)
22678399217619156974…73668889330006735921
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
4.535 × 10⁹⁸(99-digit number)
45356798435238313948…47337778660013471841
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
9.071 × 10⁹⁸(99-digit number)
90713596870476627897…94675557320026943681
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
1.814 × 10⁹⁹(100-digit number)
18142719374095325579…89351114640053887361
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
3.628 × 10⁹⁹(100-digit number)
36285438748190651158…78702229280107774721
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
7.257 × 10⁹⁹(100-digit number)
72570877496381302317…57404458560215549441
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
1.451 × 10¹⁰⁰(101-digit number)
14514175499276260463…14808917120431098881
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:57,634,801 XPM·at block #6,798,845 · updates every 60s
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