Block #2,111,245

1CCLength 10★★☆☆☆

Cunningham Chain of the First Kind · Discovered 5/11/2017, 7:33:12 AM · Difficulty 10.9035 · 4,732,467 confirmations

1CC
Cunningham Chain of the First Kind

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

Block Header
Block Hash
301509f729686d10ae31fe5c190cb9fc874abad8534df5c78f3f71e88dd89c85

Height

#2,111,245

Difficulty

10.903542

Transactions

2

Size

722 B

Version

2

Bits

0ae74e8a

Nonce

65,539,380

Timestamp

5/11/2017, 7:33:12 AM

Confirmations

4,732,467

Merkle Root

11eab7f636e82101fc43cd8cb50ded11b65c41888095f0755aa65aa9df276f43
Transactions (2)
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.

4.210 × 10⁹⁶(97-digit number)
42102789220287131506…77579004721854300159
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
4.210 × 10⁹⁶(97-digit number)
42102789220287131506…77579004721854300159
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
2
2^1 × origin − 1
8.420 × 10⁹⁶(97-digit number)
84205578440574263012…55158009443708600319
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
3
2^2 × origin − 1
1.684 × 10⁹⁷(98-digit number)
16841115688114852602…10316018887417200639
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
4
2^3 × origin − 1
3.368 × 10⁹⁷(98-digit number)
33682231376229705204…20632037774834401279
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
5
2^4 × origin − 1
6.736 × 10⁹⁷(98-digit number)
67364462752459410409…41264075549668802559
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
6
2^5 × origin − 1
1.347 × 10⁹⁸(99-digit number)
13472892550491882081…82528151099337605119
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
7
2^6 × origin − 1
2.694 × 10⁹⁸(99-digit number)
26945785100983764163…65056302198675210239
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
8
2^7 × origin − 1
5.389 × 10⁹⁸(99-digit number)
53891570201967528327…30112604397350420479
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
9
2^8 × origin − 1
1.077 × 10⁹⁹(100-digit number)
10778314040393505665…60225208794700840959
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
10
2^9 × origin − 1
2.155 × 10⁹⁹(100-digit number)
21556628080787011331…20450417589401681919
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:57,994,066 XPM·at block #6,843,711 · updates every 60s
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