Block #2,810,964

2CCLength 11★★★☆☆

Cunningham Chain of the Second Kind · Discovered 8/26/2018, 4:35:52 PM · Difficulty 11.6670 · 4,020,603 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
3ecf1a55d0e6bbc53bb58d1c88ce75988ddebc3398922017961bf10a3cc7fad7

Height

#2,810,964

Difficulty

11.666970

Transactions

3

Size

1.29 KB

Version

2

Bits

0baabe92

Nonce

1,178,502,771

Timestamp

8/26/2018, 4:35:52 PM

Confirmations

4,020,603

Merkle Root

8f12c2b14d0893f703ab0b1724085f7a70b254c132509898bcb30492c522bd69
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.

1.049 × 10⁹¹(92-digit number)
10497126723096891184…99782712678116049791
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
1.049 × 10⁹¹(92-digit number)
10497126723096891184…99782712678116049791
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
2.099 × 10⁹¹(92-digit number)
20994253446193782369…99565425356232099581
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
4.198 × 10⁹¹(92-digit number)
41988506892387564739…99130850712464199161
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
8.397 × 10⁹¹(92-digit number)
83977013784775129478…98261701424928398321
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
1.679 × 10⁹²(93-digit number)
16795402756955025895…96523402849856796641
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
3.359 × 10⁹²(93-digit number)
33590805513910051791…93046805699713593281
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
6.718 × 10⁹²(93-digit number)
67181611027820103582…86093611399427186561
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
1.343 × 10⁹³(94-digit number)
13436322205564020716…72187222798854373121
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
2.687 × 10⁹³(94-digit number)
26872644411128041432…44374445597708746241
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
5.374 × 10⁹³(94-digit number)
53745288822256082865…88748891195417492481
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
11
2^10 × origin + 1
1.074 × 10⁹⁴(95-digit number)
10749057764451216573…77497782390834984961
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:57,896,628 XPM·at block #6,831,566 · updates every 60s
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