Block #326,166

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 12/23/2013, 2:26:01 PM · Difficulty 10.1941 · 6,484,873 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
dfef7887e04ad0eaec6182d4ac2195031deccb17bcc823b3367794ba39d62b8f

Height

#326,166

Difficulty

10.194148

Transactions

13

Size

3.35 KB

Version

2

Bits

0a31b3a9

Nonce

38,141

Timestamp

12/23/2013, 2:26:01 PM

Confirmations

6,484,873

Merkle Root

3a21cda57a499974033b3ce98a58c6a38e0c2df7e218309399b29e23d6152ebb
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.

9.046 × 10⁹⁵(96-digit number)
90464287469588715965…27923192681528818401
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
9.046 × 10⁹⁵(96-digit number)
90464287469588715965…27923192681528818401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
1.809 × 10⁹⁶(97-digit number)
18092857493917743193…55846385363057636801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
3.618 × 10⁹⁶(97-digit number)
36185714987835486386…11692770726115273601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
7.237 × 10⁹⁶(97-digit number)
72371429975670972772…23385541452230547201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
1.447 × 10⁹⁷(98-digit number)
14474285995134194554…46771082904461094401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
2.894 × 10⁹⁷(98-digit number)
28948571990268389108…93542165808922188801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
5.789 × 10⁹⁷(98-digit number)
57897143980536778217…87084331617844377601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
1.157 × 10⁹⁸(99-digit number)
11579428796107355643…74168663235688755201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
2.315 × 10⁹⁸(99-digit number)
23158857592214711287…48337326471377510401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
4.631 × 10⁹⁸(99-digit number)
46317715184429422574…96674652942755020801
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:57,732,422 XPM·at block #6,811,038 · updates every 60s
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