Block #443,750

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 3/14/2014, 6:47:57 PM · Difficulty 10.3462 · 6,359,395 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
4d4e996eaba8e520b3fcd651cb4b53f5e8d478b7811fdd0bac2bf17e8153ded9

Height

#443,750

Difficulty

10.346155

Transactions

1

Size

935 B

Version

2

Bits

0a589da0

Nonce

9,123

Timestamp

3/14/2014, 6:47:57 PM

Confirmations

6,359,395

Merkle Root

3b36c44851de2365a6a2c03fe85cd51f2bf73fcac8f5c99406a9d1ef1dc7b942
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.

5.346 × 10⁹⁴(95-digit number)
53466173627300978743…24392420447262875121
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
5.346 × 10⁹⁴(95-digit number)
53466173627300978743…24392420447262875121
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
1.069 × 10⁹⁵(96-digit number)
10693234725460195748…48784840894525750241
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
2.138 × 10⁹⁵(96-digit number)
21386469450920391497…97569681789051500481
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
4.277 × 10⁹⁵(96-digit number)
42772938901840782994…95139363578103000961
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
8.554 × 10⁹⁵(96-digit number)
85545877803681565989…90278727156206001921
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
1.710 × 10⁹⁶(97-digit number)
17109175560736313197…80557454312412003841
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
3.421 × 10⁹⁶(97-digit number)
34218351121472626395…61114908624824007681
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
6.843 × 10⁹⁶(97-digit number)
68436702242945252791…22229817249648015361
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
1.368 × 10⁹⁷(98-digit number)
13687340448589050558…44459634499296030721
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
2.737 × 10⁹⁷(98-digit number)
27374680897178101116…88919268998592061441
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:57,669,193 XPM·at block #6,803,144 · updates every 60s
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