Block #330,715

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 12/26/2013, 9:03:35 PM · Difficulty 10.1676 · 6,475,971 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
a90dc44ab73d9791091ef837d28cca95b7feac167ba1715cd6084e9c51071f91

Height

#330,715

Difficulty

10.167569

Transactions

21

Size

6.97 KB

Version

2

Bits

0a2ae5cf

Nonce

77,853

Timestamp

12/26/2013, 9:03:35 PM

Confirmations

6,475,971

Merkle Root

4d50ca1f14b36c3dfc3581b9888de3c06f3aa497ff07b91c320ab05ee72c0a87
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.

3.282 × 10⁹³(94-digit number)
32822986483684861550…26793776408847903621
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
3.282 × 10⁹³(94-digit number)
32822986483684861550…26793776408847903621
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
6.564 × 10⁹³(94-digit number)
65645972967369723100…53587552817695807241
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
1.312 × 10⁹⁴(95-digit number)
13129194593473944620…07175105635391614481
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
2.625 × 10⁹⁴(95-digit number)
26258389186947889240…14350211270783228961
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
5.251 × 10⁹⁴(95-digit number)
52516778373895778480…28700422541566457921
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
1.050 × 10⁹⁵(96-digit number)
10503355674779155696…57400845083132915841
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
2.100 × 10⁹⁵(96-digit number)
21006711349558311392…14801690166265831681
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
4.201 × 10⁹⁵(96-digit number)
42013422699116622784…29603380332531663361
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
8.402 × 10⁹⁵(96-digit number)
84026845398233245569…59206760665063326721
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
1.680 × 10⁹⁶(97-digit number)
16805369079646649113…18413521330126653441
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:57,697,582 XPM·at block #6,806,685 · updates every 60s
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