Block #332,783

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 12/28/2013, 7:50:43 AM · Difficulty 10.1654 · 6,494,561 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
139cbaf6e07cfe91f814f303cbd729662da1974d2d198f9cd4484c483a3b6db5

Height

#332,783

Difficulty

10.165379

Transactions

5

Size

1.71 KB

Version

2

Bits

0a2a5649

Nonce

50,530

Timestamp

12/28/2013, 7:50:43 AM

Confirmations

6,494,561

Merkle Root

0f093bb091f7cf22eb103b708819eb881cd2c6dbb0b1f94c3655d6d2073e0f50
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.

1.312 × 10⁹⁷(98-digit number)
13123118156372777228…20273354861776793601
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
1.312 × 10⁹⁷(98-digit number)
13123118156372777228…20273354861776793601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
2.624 × 10⁹⁷(98-digit number)
26246236312745554457…40546709723553587201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
5.249 × 10⁹⁷(98-digit number)
52492472625491108914…81093419447107174401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
1.049 × 10⁹⁸(99-digit number)
10498494525098221782…62186838894214348801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
2.099 × 10⁹⁸(99-digit number)
20996989050196443565…24373677788428697601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
4.199 × 10⁹⁸(99-digit number)
41993978100392887131…48747355576857395201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
8.398 × 10⁹⁸(99-digit number)
83987956200785774263…97494711153714790401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
1.679 × 10⁹⁹(100-digit number)
16797591240157154852…94989422307429580801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
3.359 × 10⁹⁹(100-digit number)
33595182480314309705…89978844614859161601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
6.719 × 10⁹⁹(100-digit number)
67190364960628619410…79957689229718323201
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:57,862,861 XPM·at block #6,827,343 · updates every 60s
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