Block #3,010,787

2CCLength 11★★★☆☆

Cunningham Chain of the Second Kind · Discovered 1/15/2019, 2:05:18 PM · Difficulty 11.1991 · 3,834,383 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
4e3c256a61e1cfc2a2e57758582464e9c2e58c3514a8622edfa0cda9e6d61831

Height

#3,010,787

Difficulty

11.199081

Transactions

7

Size

2.79 KB

Version

2

Bits

0b32f6f9

Nonce

916,058,680

Timestamp

1/15/2019, 2:05:18 PM

Confirmations

3,834,383

Merkle Root

36e5cb205370f735c8d3a1e8d80d2d9b4c81504a54a6e5a153f3512a22659f10
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.

1.180 × 10⁹⁵(96-digit number)
11805103342207258895…01105774855562158841
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
1.180 × 10⁹⁵(96-digit number)
11805103342207258895…01105774855562158841
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
2.361 × 10⁹⁵(96-digit number)
23610206684414517790…02211549711124317681
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
4.722 × 10⁹⁵(96-digit number)
47220413368829035580…04423099422248635361
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
9.444 × 10⁹⁵(96-digit number)
94440826737658071161…08846198844497270721
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
1.888 × 10⁹⁶(97-digit number)
18888165347531614232…17692397688994541441
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
3.777 × 10⁹⁶(97-digit number)
37776330695063228464…35384795377989082881
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
7.555 × 10⁹⁶(97-digit number)
75552661390126456929…70769590755978165761
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
1.511 × 10⁹⁷(98-digit number)
15110532278025291385…41539181511956331521
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
3.022 × 10⁹⁷(98-digit number)
30221064556050582771…83078363023912663041
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
6.044 × 10⁹⁷(98-digit number)
60442129112101165543…66156726047825326081
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
11
2^10 × origin + 1
1.208 × 10⁹⁸(99-digit number)
12088425822420233108…32313452095650652161
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:58,005,791 XPM·at block #6,845,169 · updates every 60s
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