Block #2,862,482

2CCLength 11★★★☆☆

Cunningham Chain of the Second Kind · Discovered 10/1/2018, 9:39:12 AM · Difficulty 11.6749 · 3,979,820 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
fe9c6a5468493a97c7083db3cc4cab8f8f970a62093f3070e739ae77d55ac4d1

Height

#2,862,482

Difficulty

11.674948

Transactions

30

Size

10.34 KB

Version

2

Bits

0bacc95c

Nonce

1,778,079,985

Timestamp

10/1/2018, 9:39:12 AM

Confirmations

3,979,820

Merkle Root

55844ea6ed0dfffd2095284dd323e4692f140f9597435facdeebb015fb1d315a
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.

3.506 × 10⁹⁴(95-digit number)
35066647934345568192…06287259822268254081
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
3.506 × 10⁹⁴(95-digit number)
35066647934345568192…06287259822268254081
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
7.013 × 10⁹⁴(95-digit number)
70133295868691136385…12574519644536508161
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
1.402 × 10⁹⁵(96-digit number)
14026659173738227277…25149039289073016321
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
2.805 × 10⁹⁵(96-digit number)
28053318347476454554…50298078578146032641
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
5.610 × 10⁹⁵(96-digit number)
56106636694952909108…00596157156292065281
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
1.122 × 10⁹⁶(97-digit number)
11221327338990581821…01192314312584130561
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
2.244 × 10⁹⁶(97-digit number)
22442654677981163643…02384628625168261121
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
4.488 × 10⁹⁶(97-digit number)
44885309355962327286…04769257250336522241
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
8.977 × 10⁹⁶(97-digit number)
89770618711924654573…09538514500673044481
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
1.795 × 10⁹⁷(98-digit number)
17954123742384930914…19077029001346088961
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
11
2^10 × origin + 1
3.590 × 10⁹⁷(98-digit number)
35908247484769861829…38154058002692177921
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:57,982,821 XPM·at block #6,842,301 · updates every 60s
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