Block #2,083,127

2CCLength 11★★★☆☆

Cunningham Chain of the Second Kind · Discovered 4/22/2017, 6:56:41 PM · Difficulty 10.8706 · 4,750,089 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
cb45254796ebfa1895be09716ea93ee70dd90557aff7c3ea6f366af3c45a318a

Height

#2,083,127

Difficulty

10.870592

Transactions

2

Size

1.40 KB

Version

2

Bits

0adedf1a

Nonce

1,141,780,598

Timestamp

4/22/2017, 6:56:41 PM

Confirmations

4,750,089

Merkle Root

69f62397543fe8ea15ace349426a88093e2e96ac38fb93c4111c7f026b1214b7
Transactions (2)
1 in → 1 out8.4700 XPM110 B
8 in → 1 out543.8600 XPM1.20 KB
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.

1.817 × 10⁹¹(92-digit number)
18172929200872549972…65913319200897933061
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
1.817 × 10⁹¹(92-digit number)
18172929200872549972…65913319200897933061
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
3.634 × 10⁹¹(92-digit number)
36345858401745099944…31826638401795866121
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
7.269 × 10⁹¹(92-digit number)
72691716803490199889…63653276803591732241
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
1.453 × 10⁹²(93-digit number)
14538343360698039977…27306553607183464481
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
2.907 × 10⁹²(93-digit number)
29076686721396079955…54613107214366928961
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
5.815 × 10⁹²(93-digit number)
58153373442792159911…09226214428733857921
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
1.163 × 10⁹³(94-digit number)
11630674688558431982…18452428857467715841
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
2.326 × 10⁹³(94-digit number)
23261349377116863964…36904857714935431681
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
4.652 × 10⁹³(94-digit number)
46522698754233727929…73809715429870863361
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
9.304 × 10⁹³(94-digit number)
93045397508467455858…47619430859741726721
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
11
2^10 × origin + 1
1.860 × 10⁹⁴(95-digit number)
18609079501693491171…95238861719483453441
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:57,909,914 XPM·at block #6,833,215 · updates every 60s
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