Block #4,029,494

1CCLength 10★★☆☆☆

Cunningham Chain of the First Kind · Discovered 1/10/2021, 2:11:48 AM · Difficulty 10.8339 · 2,797,614 confirmations

1CC
Cunningham Chain of the First Kind

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

Block Header
Block Hash
3a38979fd45b47fe14defb1d2800cc4cb5fb00d0fb8e96b6e6cb24767281e16a

Height

#4,029,494

Difficulty

10.833909

Transactions

6

Size

3.12 KB

Version

2

Bits

0ad57b0d

Nonce

16,417,610

Timestamp

1/10/2021, 2:11:48 AM

Confirmations

2,797,614

Merkle Root

ff9ae1d5af7797b2279880d69f039f96fdad766ead02cfa85ae9383d60451150
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.

3.132 × 10⁹⁵(96-digit number)
31328745929260771554…21379337987072724479
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
3.132 × 10⁹⁵(96-digit number)
31328745929260771554…21379337987072724479
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
2
2^1 × origin − 1
6.265 × 10⁹⁵(96-digit number)
62657491858521543108…42758675974145448959
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
3
2^2 × origin − 1
1.253 × 10⁹⁶(97-digit number)
12531498371704308621…85517351948290897919
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
4
2^3 × origin − 1
2.506 × 10⁹⁶(97-digit number)
25062996743408617243…71034703896581795839
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
5
2^4 × origin − 1
5.012 × 10⁹⁶(97-digit number)
50125993486817234486…42069407793163591679
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
6
2^5 × origin − 1
1.002 × 10⁹⁷(98-digit number)
10025198697363446897…84138815586327183359
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
7
2^6 × origin − 1
2.005 × 10⁹⁷(98-digit number)
20050397394726893794…68277631172654366719
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
8
2^7 × origin − 1
4.010 × 10⁹⁷(98-digit number)
40100794789453787589…36555262345308733439
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
9
2^8 × origin − 1
8.020 × 10⁹⁷(98-digit number)
80201589578907575178…73110524690617466879
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
10
2^9 × origin − 1
1.604 × 10⁹⁸(99-digit number)
16040317915781515035…46221049381234933759
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 First 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 1CC formula:

1CC: p₁ (first prime), p₂ = 2p₁ + 1, p₃ = 2p₂ + 1, …
Circulating Supply:57,861,042 XPM·at block #6,827,107 · updates every 60s
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