Block #457,767

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 3/24/2014, 3:26:42 AM · Difficulty 10.4194 · 6,360,069 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
76f69470e8b6e087fd0ba4815e8b0c0718fce8de0143c356d7660e357735ec98

Height

#457,767

Difficulty

10.419384

Transactions

9

Size

1.89 KB

Version

2

Bits

0a6b5cc7

Nonce

1,367

Timestamp

3/24/2014, 3:26:42 AM

Confirmations

6,360,069

Merkle Root

a4c4a233599aa6ed527b6c504295c9c6709572b02e8e23eecf3642d542c3e884
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.

4.989 × 10⁹⁷(98-digit number)
49895874009658622572…03661837171259142401
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
4.989 × 10⁹⁷(98-digit number)
49895874009658622572…03661837171259142401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
9.979 × 10⁹⁷(98-digit number)
99791748019317245144…07323674342518284801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
1.995 × 10⁹⁸(99-digit number)
19958349603863449028…14647348685036569601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
3.991 × 10⁹⁸(99-digit number)
39916699207726898057…29294697370073139201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
7.983 × 10⁹⁸(99-digit number)
79833398415453796115…58589394740146278401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
1.596 × 10⁹⁹(100-digit number)
15966679683090759223…17178789480292556801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
3.193 × 10⁹⁹(100-digit number)
31933359366181518446…34357578960585113601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
6.386 × 10⁹⁹(100-digit number)
63866718732363036892…68715157921170227201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
1.277 × 10¹⁰⁰(101-digit number)
12773343746472607378…37430315842340454401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
2.554 × 10¹⁰⁰(101-digit number)
25546687492945214756…74860631684680908801
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:57,786,752 XPM·at block #6,817,835 · updates every 60s
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