Block #3,233,123

2CCLength 12★★★★☆

Cunningham Chain of the Second Kind · Discovered 6/20/2019, 8:29:28 AM · Difficulty 10.9961 · 3,606,254 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
a895eacf4cac149616b86c449777db48947848587799ce45a1f1033be800545a

Height

#3,233,123

Difficulty

10.996086

Transactions

5

Size

1.16 KB

Version

2

Bits

0afeff80

Nonce

199,916,685

Timestamp

6/20/2019, 8:29:28 AM

Confirmations

3,606,254

Merkle Root

2425b623b4f82dc0f7b9942445291f05d25036f7b34a7df2158d5503987a841b
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.

8.623 × 10⁹¹(92-digit number)
86237208641455225245…72106166310811495681
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
8.623 × 10⁹¹(92-digit number)
86237208641455225245…72106166310811495681
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
1.724 × 10⁹²(93-digit number)
17247441728291045049…44212332621622991361
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
3.449 × 10⁹²(93-digit number)
34494883456582090098…88424665243245982721
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
6.898 × 10⁹²(93-digit number)
68989766913164180196…76849330486491965441
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
1.379 × 10⁹³(94-digit number)
13797953382632836039…53698660972983930881
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
2.759 × 10⁹³(94-digit number)
27595906765265672078…07397321945967861761
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
5.519 × 10⁹³(94-digit number)
55191813530531344157…14794643891935723521
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
1.103 × 10⁹⁴(95-digit number)
11038362706106268831…29589287783871447041
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
2.207 × 10⁹⁴(95-digit number)
22076725412212537662…59178575567742894081
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
4.415 × 10⁹⁴(95-digit number)
44153450824425075325…18357151135485788161
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
11
2^10 × origin + 1
8.830 × 10⁹⁴(95-digit number)
88306901648850150651…36714302270971576321
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
12
2^11 × origin + 1
1.766 × 10⁹⁵(96-digit number)
17661380329770030130…73428604541943152641
Verify on FactorDB ↗Wolfram Alpha ↗

What this block proved

The miner who found this block proved the existence of 12 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
ExceptionalChain length 12

Around 1 in 10,000 blocks. A significant mathematical achievement.

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:57,959,299 XPM·at block #6,839,376 · updates every 60s
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