Block #314,730

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 12/16/2013, 3:20:32 AM · Difficulty 10.0718 · 6,496,269 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
8d989028057cf8521e0e93c9f0e29177994f5d0f57f91b3d19c5f2b21a464eb6

Height

#314,730

Difficulty

10.071843

Transactions

13

Size

3.13 KB

Version

2

Bits

0a126451

Nonce

7,081

Timestamp

12/16/2013, 3:20:32 AM

Confirmations

6,496,269

Merkle Root

41fe6313482edb17f474a8700c67af4facef5b1c04c83f137c6ee35ce4cf920b
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.

5.272 × 10¹⁰¹(102-digit number)
52726684792957443498…56937203280778924801
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
5.272 × 10¹⁰¹(102-digit number)
52726684792957443498…56937203280778924801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
1.054 × 10¹⁰²(103-digit number)
10545336958591488699…13874406561557849601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
2.109 × 10¹⁰²(103-digit number)
21090673917182977399…27748813123115699201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
4.218 × 10¹⁰²(103-digit number)
42181347834365954798…55497626246231398401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
8.436 × 10¹⁰²(103-digit number)
84362695668731909597…10995252492462796801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
1.687 × 10¹⁰³(104-digit number)
16872539133746381919…21990504984925593601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
3.374 × 10¹⁰³(104-digit number)
33745078267492763838…43981009969851187201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
6.749 × 10¹⁰³(104-digit number)
67490156534985527677…87962019939702374401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
1.349 × 10¹⁰⁴(105-digit number)
13498031306997105535…75924039879404748801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
2.699 × 10¹⁰⁴(105-digit number)
26996062613994211071…51848079758809497601
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:57,732,095 XPM·at block #6,810,998 · updates every 60s
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