Block #392,270

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 2/6/2014, 8:47:30 AM · Difficulty 10.4366 · 6,434,959 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
03855a4c7852efb0c286968d4c0d123c8e6f43a4f80e326b924c04bd8892bff2

Height

#392,270

Difficulty

10.436641

Transactions

11

Size

4.08 KB

Version

2

Bits

0a6fc7b1

Nonce

101,454

Timestamp

2/6/2014, 8:47:30 AM

Confirmations

6,434,959

Merkle Root

ac87be071a98851dcf4136227402b66a5e700faf154c1a318902a5ac8d2be446
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.

4.529 × 10¹⁰¹(102-digit number)
45299611581967570082…80915499992229985921
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
4.529 × 10¹⁰¹(102-digit number)
45299611581967570082…80915499992229985921
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
9.059 × 10¹⁰¹(102-digit number)
90599223163935140165…61830999984459971841
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
1.811 × 10¹⁰²(103-digit number)
18119844632787028033…23661999968919943681
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
3.623 × 10¹⁰²(103-digit number)
36239689265574056066…47323999937839887361
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
7.247 × 10¹⁰²(103-digit number)
72479378531148112132…94647999875679774721
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
1.449 × 10¹⁰³(104-digit number)
14495875706229622426…89295999751359549441
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
2.899 × 10¹⁰³(104-digit number)
28991751412459244852…78591999502719098881
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
5.798 × 10¹⁰³(104-digit number)
57983502824918489705…57183999005438197761
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
1.159 × 10¹⁰⁴(105-digit number)
11596700564983697941…14367998010876395521
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
2.319 × 10¹⁰⁴(105-digit number)
23193401129967395882…28735996021752791041
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:57,861,931 XPM·at block #6,827,228 · updates every 60s
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