Block #337,354

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 12/31/2013, 3:05:20 PM · Difficulty 10.1365 · 6,454,626 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
be823dd894eebf17391da27950a8612f7883cf8d8d321b00a3309d5cd3b3ae8d

Height

#337,354

Difficulty

10.136461

Transactions

15

Size

15.04 KB

Version

2

Bits

0a22ef23

Nonce

29,766

Timestamp

12/31/2013, 3:05:20 PM

Confirmations

6,454,626

Merkle Root

13711a60d5d33409eefffbc4d6a37f7b8a717188ee31351b8226f4157a4fbb77
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.

4.108 × 10⁹⁷(98-digit number)
41084729696615341685…31738550566123343841
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
4.108 × 10⁹⁷(98-digit number)
41084729696615341685…31738550566123343841
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
8.216 × 10⁹⁷(98-digit number)
82169459393230683370…63477101132246687681
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
1.643 × 10⁹⁸(99-digit number)
16433891878646136674…26954202264493375361
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
3.286 × 10⁹⁸(99-digit number)
32867783757292273348…53908404528986750721
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
6.573 × 10⁹⁸(99-digit number)
65735567514584546696…07816809057973501441
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
1.314 × 10⁹⁹(100-digit number)
13147113502916909339…15633618115947002881
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
2.629 × 10⁹⁹(100-digit number)
26294227005833818678…31267236231894005761
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
5.258 × 10⁹⁹(100-digit number)
52588454011667637357…62534472463788011521
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
1.051 × 10¹⁰⁰(101-digit number)
10517690802333527471…25068944927576023041
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
2.103 × 10¹⁰⁰(101-digit number)
21035381604667054942…50137889855152046081
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:57,579,800 XPM·at block #6,791,979 · updates every 60s
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