Block #565,177

2CCLength 11★★★☆☆

Cunningham Chain of the Second Kind · Discovered 5/28/2014, 4:09:38 AM · Difficulty 10.9648 · 6,244,499 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
7a474b6aee6cc1aca12216d283b9ceb0c6e30a87502e250797c26689547f83d5

Height

#565,177

Difficulty

10.964784

Transactions

4

Size

1.59 KB

Version

2

Bits

0af6fc10

Nonce

254,340,316

Timestamp

5/28/2014, 4:09:38 AM

Confirmations

6,244,499

Merkle Root

62946ffad4d18d282822112e9bccba5e4bb498cd291b9acfe804f031ec15f5c6
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.

6.627 × 10¹⁰⁰(101-digit number)
66270840314029649773…58005272439925606401
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
6.627 × 10¹⁰⁰(101-digit number)
66270840314029649773…58005272439925606401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
1.325 × 10¹⁰¹(102-digit number)
13254168062805929954…16010544879851212801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
2.650 × 10¹⁰¹(102-digit number)
26508336125611859909…32021089759702425601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
5.301 × 10¹⁰¹(102-digit number)
53016672251223719818…64042179519404851201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
1.060 × 10¹⁰²(103-digit number)
10603334450244743963…28084359038809702401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
2.120 × 10¹⁰²(103-digit number)
21206668900489487927…56168718077619404801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
4.241 × 10¹⁰²(103-digit number)
42413337800978975854…12337436155238809601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
8.482 × 10¹⁰²(103-digit number)
84826675601957951709…24674872310477619201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
1.696 × 10¹⁰³(104-digit number)
16965335120391590341…49349744620955238401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
3.393 × 10¹⁰³(104-digit number)
33930670240783180683…98699489241910476801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
11
2^10 × origin + 1
6.786 × 10¹⁰³(104-digit number)
67861340481566361367…97398978483820953601
Verify on FactorDB ↗Wolfram Alpha ↗

What this block proved

The miner who found this block proved the existence of 11 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
RareChain length 11

Approximately 1 in 1,000 blocks. Noteworthy discoveries.

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:57,721,484 XPM·at block #6,809,675 · updates every 60s
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