Block #326,109

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 12/23/2013, 1:37:35 PM · Difficulty 10.1934 · 6,498,774 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
0b3328f0f9f37f6b3e44004b6e3444e9531f28f734552e2c210fc2ed92725f1b

Height

#326,109

Difficulty

10.193395

Transactions

8

Size

2.56 KB

Version

2

Bits

0a318255

Nonce

81,130

Timestamp

12/23/2013, 1:37:35 PM

Confirmations

6,498,774

Merkle Root

8d12308a3863ec09d7168c121860dcb70928c7b83957222e8c522d1e981a7194
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.

8.253 × 10¹¹³(114-digit number)
82533714519376282239…79419015700117382401
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
8.253 × 10¹¹³(114-digit number)
82533714519376282239…79419015700117382401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
1.650 × 10¹¹⁴(115-digit number)
16506742903875256447…58838031400234764801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
3.301 × 10¹¹⁴(115-digit number)
33013485807750512895…17676062800469529601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
6.602 × 10¹¹⁴(115-digit number)
66026971615501025791…35352125600939059201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
1.320 × 10¹¹⁵(116-digit number)
13205394323100205158…70704251201878118401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
2.641 × 10¹¹⁵(116-digit number)
26410788646200410316…41408502403756236801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
5.282 × 10¹¹⁵(116-digit number)
52821577292400820633…82817004807512473601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
1.056 × 10¹¹⁶(117-digit number)
10564315458480164126…65634009615024947201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
2.112 × 10¹¹⁶(117-digit number)
21128630916960328253…31268019230049894401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
4.225 × 10¹¹⁶(117-digit number)
42257261833920656506…62536038460099788801
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:57,843,146 XPM·at block #6,824,882 · updates every 60s
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