Block #2,634,111

2CCLength 11★★★☆☆

Cunningham Chain of the Second Kind · Discovered 4/28/2018, 6:36:48 PM · Difficulty 11.2232 · 4,196,873 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
7e56950a9dd8c6731591e4b4b092450f3192e6166fff290dc96ebf523de53fd3

Height

#2,634,111

Difficulty

11.223246

Transactions

2

Size

723 B

Version

2

Bits

0b3926ab

Nonce

328,390,004

Timestamp

4/28/2018, 6:36:48 PM

Confirmations

4,196,873

Merkle Root

47cfc6620e51af1977637bb763eb9032eaba7ac0f003b208605ef24b30462f72
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.

3.972 × 10⁹⁶(97-digit number)
39724978493528016408…04467367582708858881
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
3.972 × 10⁹⁶(97-digit number)
39724978493528016408…04467367582708858881
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
7.944 × 10⁹⁶(97-digit number)
79449956987056032817…08934735165417717761
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
1.588 × 10⁹⁷(98-digit number)
15889991397411206563…17869470330835435521
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
3.177 × 10⁹⁷(98-digit number)
31779982794822413126…35738940661670871041
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
6.355 × 10⁹⁷(98-digit number)
63559965589644826253…71477881323341742081
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
1.271 × 10⁹⁸(99-digit number)
12711993117928965250…42955762646683484161
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
2.542 × 10⁹⁸(99-digit number)
25423986235857930501…85911525293366968321
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
5.084 × 10⁹⁸(99-digit number)
50847972471715861002…71823050586733936641
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
1.016 × 10⁹⁹(100-digit number)
10169594494343172200…43646101173467873281
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
2.033 × 10⁹⁹(100-digit number)
20339188988686344401…87292202346935746561
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
11
2^10 × origin + 1
4.067 × 10⁹⁹(100-digit number)
40678377977372688802…74584404693871493121
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:57,892,013 XPM·at block #6,830,983 · updates every 60s
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