Block #2,134,073

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 5/26/2017, 11:58:22 PM · Difficulty 10.9088 · 4,709,401 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
fca25d016c1ec5fd40f0414d77106e7f77dbd39bef96571fa47c87f95fd805db

Height

#2,134,073

Difficulty

10.908767

Transactions

2

Size

426 B

Version

2

Bits

0ae8a4f7

Nonce

1,275,888,226

Timestamp

5/26/2017, 11:58:22 PM

Confirmations

4,709,401

Merkle Root

602d11e330bda1587ec865f521096ce574a328f48f185146ccfdd075629141ba
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.

6.958 × 10⁹³(94-digit number)
69582580078961778693…65469155166141606401
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
6.958 × 10⁹³(94-digit number)
69582580078961778693…65469155166141606401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
1.391 × 10⁹⁴(95-digit number)
13916516015792355738…30938310332283212801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
2.783 × 10⁹⁴(95-digit number)
27833032031584711477…61876620664566425601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
5.566 × 10⁹⁴(95-digit number)
55666064063169422954…23753241329132851201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
1.113 × 10⁹⁵(96-digit number)
11133212812633884590…47506482658265702401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
2.226 × 10⁹⁵(96-digit number)
22266425625267769181…95012965316531404801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
4.453 × 10⁹⁵(96-digit number)
44532851250535538363…90025930633062809601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
8.906 × 10⁹⁵(96-digit number)
89065702501071076727…80051861266125619201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
1.781 × 10⁹⁶(97-digit number)
17813140500214215345…60103722532251238401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
3.562 × 10⁹⁶(97-digit number)
35626281000428430690…20207445064502476801
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:57,992,161 XPM·at block #6,843,473 · updates every 60s
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