Block #451,146

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 3/19/2014, 5:46:17 PM · Difficulty 10.3821 · 6,352,906 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
189371c7d51ba601e0f9dd8fc8de890c200826f93b1942fdae27e3a39a945f79

Height

#451,146

Difficulty

10.382129

Transactions

2

Size

832 B

Version

2

Bits

0a61d337

Nonce

170

Timestamp

3/19/2014, 5:46:17 PM

Confirmations

6,352,906

Merkle Root

cca302f6528f99e419fe29305f61f1a0668b5ac428355eac8d39ea7721050721
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.

6.832 × 10⁹⁶(97-digit number)
68323378650973032205…27980021353962734141
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
6.832 × 10⁹⁶(97-digit number)
68323378650973032205…27980021353962734141
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
1.366 × 10⁹⁷(98-digit number)
13664675730194606441…55960042707925468281
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
2.732 × 10⁹⁷(98-digit number)
27329351460389212882…11920085415850936561
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
5.465 × 10⁹⁷(98-digit number)
54658702920778425764…23840170831701873121
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
1.093 × 10⁹⁸(99-digit number)
10931740584155685152…47680341663403746241
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
2.186 × 10⁹⁸(99-digit number)
21863481168311370305…95360683326807492481
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
4.372 × 10⁹⁸(99-digit number)
43726962336622740611…90721366653614984961
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
8.745 × 10⁹⁸(99-digit number)
87453924673245481222…81442733307229969921
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
1.749 × 10⁹⁹(100-digit number)
17490784934649096244…62885466614459939841
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
3.498 × 10⁹⁹(100-digit number)
34981569869298192489…25770933228919879681
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:57,676,471 XPM·at block #6,804,051 · updates every 60s
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