Block #3,470,143

2CCLength 11★★★☆☆

Cunningham Chain of the Second Kind · Discovered 12/10/2019, 6:44:09 PM · Difficulty 10.9792 · 3,373,578 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
736ab2312489cc8c94da901d02457c4da7b843da40d89dcad08667880453c12e

Height

#3,470,143

Difficulty

10.979184

Transactions

3

Size

3.36 KB

Version

2

Bits

0afaabc7

Nonce

1,048,280,782

Timestamp

12/10/2019, 6:44:09 PM

Confirmations

3,373,578

Merkle Root

a4fa8805fd7be7e9b356333bc80a5556fac09b714be4e6a76398b321543e20e1
Transactions (3)
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.

1.792 × 10⁹³(94-digit number)
17920967608362533982…07812728582711387101
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
1.792 × 10⁹³(94-digit number)
17920967608362533982…07812728582711387101
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
3.584 × 10⁹³(94-digit number)
35841935216725067965…15625457165422774201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
7.168 × 10⁹³(94-digit number)
71683870433450135931…31250914330845548401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
1.433 × 10⁹⁴(95-digit number)
14336774086690027186…62501828661691096801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
2.867 × 10⁹⁴(95-digit number)
28673548173380054372…25003657323382193601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
5.734 × 10⁹⁴(95-digit number)
57347096346760108745…50007314646764387201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
1.146 × 10⁹⁵(96-digit number)
11469419269352021749…00014629293528774401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
2.293 × 10⁹⁵(96-digit number)
22938838538704043498…00029258587057548801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
4.587 × 10⁹⁵(96-digit number)
45877677077408086996…00058517174115097601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
9.175 × 10⁹⁵(96-digit number)
91755354154816173992…00117034348230195201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
11
2^10 × origin + 1
1.835 × 10⁹⁶(97-digit number)
18351070830963234798…00234068696460390401
Verify on FactorDB ↗Wolfram Alpha ↗

What this block proved

The miner who found this block proved the existence of 11 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
RareChain length 11

Approximately 1 in 1,000 blocks. Noteworthy discoveries.

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:57,994,138 XPM·at block #6,843,720 · updates every 60s
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