Block #451,846

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 3/20/2014, 5:50:50 AM · Difficulty 10.3792 · 6,356,212 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
4a645b08ed0bd77c4b0405d1cba89ab8ade9d4664179d8a17641f7a8543f76db

Height

#451,846

Difficulty

10.379249

Transactions

2

Size

547 B

Version

2

Bits

0a611678

Nonce

73,947

Timestamp

3/20/2014, 5:50:50 AM

Confirmations

6,356,212

Merkle Root

6ca03b24f92b3244b1d3b627fb672d37ff36b56620424802ec78e5e3769c887b
Transactions (2)
1 in → 1 out9.2800 XPM116 B
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.

4.047 × 10⁹⁶(97-digit number)
40472250335476289909…15990595377056958081
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
4.047 × 10⁹⁶(97-digit number)
40472250335476289909…15990595377056958081
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
8.094 × 10⁹⁶(97-digit number)
80944500670952579818…31981190754113916161
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
1.618 × 10⁹⁷(98-digit number)
16188900134190515963…63962381508227832321
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
3.237 × 10⁹⁷(98-digit number)
32377800268381031927…27924763016455664641
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
6.475 × 10⁹⁷(98-digit number)
64755600536762063855…55849526032911329281
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
1.295 × 10⁹⁸(99-digit number)
12951120107352412771…11699052065822658561
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
2.590 × 10⁹⁸(99-digit number)
25902240214704825542…23398104131645317121
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
5.180 × 10⁹⁸(99-digit number)
51804480429409651084…46796208263290634241
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
1.036 × 10⁹⁹(100-digit number)
10360896085881930216…93592416526581268481
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
2.072 × 10⁹⁹(100-digit number)
20721792171763860433…87184833053162536961
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:57,708,508 XPM·at block #6,808,057 · updates every 60s
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