Block #3,932,097

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 11/2/2020, 4:45:09 PM · Difficulty 10.8633 · 2,911,002 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
81be4e08cb5230000751ffd8d61deb9b065b6dd830e152350d00c995ba546a7b

Height

#3,932,097

Difficulty

10.863330

Transactions

2

Size

1.71 KB

Version

2

Bits

0add032c

Nonce

263,931,610

Timestamp

11/2/2020, 4:45:09 PM

Confirmations

2,911,002

Merkle Root

4d6e4e0e008919670735d445a9ceb02d722eeb42fb7d9a68c9f8099121ff2f0b
Transactions (2)
1 in → 1 out8.4800 XPM109 B
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.

9.259 × 10⁹⁶(97-digit number)
92596738185524077829…66441630302636810241
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
9.259 × 10⁹⁶(97-digit number)
92596738185524077829…66441630302636810241
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
1.851 × 10⁹⁷(98-digit number)
18519347637104815565…32883260605273620481
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
3.703 × 10⁹⁷(98-digit number)
37038695274209631131…65766521210547240961
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
7.407 × 10⁹⁷(98-digit number)
74077390548419262263…31533042421094481921
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
1.481 × 10⁹⁸(99-digit number)
14815478109683852452…63066084842188963841
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
2.963 × 10⁹⁸(99-digit number)
29630956219367704905…26132169684377927681
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
5.926 × 10⁹⁸(99-digit number)
59261912438735409810…52264339368755855361
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
1.185 × 10⁹⁹(100-digit number)
11852382487747081962…04528678737511710721
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
2.370 × 10⁹⁹(100-digit number)
23704764975494163924…09057357475023421441
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
4.740 × 10⁹⁹(100-digit number)
47409529950988327848…18114714950046842881
Verify on FactorDB ↗Wolfram Alpha ↗

What this block proved

The miner who found this block proved the existence of 10 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
UncommonChain length 10

Roughly 1 in 100 blocks. Solid but expected in a healthy network.

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:57,989,155 XPM·at block #6,843,098 · updates every 60s
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