Block #329,103

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 12/25/2013, 5:49:52 PM · Difficulty 10.1708 · 6,495,573 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
915d5647efc418bc66152bf3d828a230697112d45ba11dec1dc331e0c2765a11

Height

#329,103

Difficulty

10.170801

Transactions

6

Size

1.74 KB

Version

2

Bits

0a2bb995

Nonce

87,950

Timestamp

12/25/2013, 5:49:52 PM

Confirmations

6,495,573

Merkle Root

6995bf2e5ecfd5d5a909b0c64515b2cf7f8cf5875c83b2d0dbf42ceafcd3654f
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.

3.353 × 10¹⁰⁷(108-digit number)
33532472238799857669…85195999840087096401
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
3.353 × 10¹⁰⁷(108-digit number)
33532472238799857669…85195999840087096401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
6.706 × 10¹⁰⁷(108-digit number)
67064944477599715338…70391999680174192801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
1.341 × 10¹⁰⁸(109-digit number)
13412988895519943067…40783999360348385601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
2.682 × 10¹⁰⁸(109-digit number)
26825977791039886135…81567998720696771201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
5.365 × 10¹⁰⁸(109-digit number)
53651955582079772270…63135997441393542401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
1.073 × 10¹⁰⁹(110-digit number)
10730391116415954454…26271994882787084801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
2.146 × 10¹⁰⁹(110-digit number)
21460782232831908908…52543989765574169601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
4.292 × 10¹⁰⁹(110-digit number)
42921564465663817816…05087979531148339201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
8.584 × 10¹⁰⁹(110-digit number)
85843128931327635633…10175959062296678401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
1.716 × 10¹¹⁰(111-digit number)
17168625786265527126…20351918124593356801
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:57,841,472 XPM·at block #6,824,675 · updates every 60s
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