Block #326,359

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 12/23/2013, 6:06:25 PM · Difficulty 10.1907 · 6,474,975 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
5e19eaba18c9f1caedd55874e7e7a173070b1f6079287027316c6494abd5cc89

Height

#326,359

Difficulty

10.190742

Transactions

21

Size

6.80 KB

Version

2

Bits

0a30d470

Nonce

317,569

Timestamp

12/23/2013, 6:06:25 PM

Confirmations

6,474,975

Merkle Root

c25a0654878ce3a0f4c22176224bc7cfe9fdeea5bedc57cca42a60f2aad10829
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.

9.730 × 10¹⁰⁰(101-digit number)
97301766558360506715…92274398580171816161
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
9.730 × 10¹⁰⁰(101-digit number)
97301766558360506715…92274398580171816161
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
1.946 × 10¹⁰¹(102-digit number)
19460353311672101343…84548797160343632321
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
3.892 × 10¹⁰¹(102-digit number)
38920706623344202686…69097594320687264641
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
7.784 × 10¹⁰¹(102-digit number)
77841413246688405372…38195188641374529281
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
1.556 × 10¹⁰²(103-digit number)
15568282649337681074…76390377282749058561
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
3.113 × 10¹⁰²(103-digit number)
31136565298675362149…52780754565498117121
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
6.227 × 10¹⁰²(103-digit number)
62273130597350724298…05561509130996234241
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
1.245 × 10¹⁰³(104-digit number)
12454626119470144859…11123018261992468481
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
2.490 × 10¹⁰³(104-digit number)
24909252238940289719…22246036523984936961
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
4.981 × 10¹⁰³(104-digit number)
49818504477880579438…44492073047969873921
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:57,654,741 XPM·at block #6,801,333 · updates every 60s
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