Block #450,847

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 3/19/2014, 1:13:46 PM · Difficulty 10.3786 · 6,365,827 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
2b99b7ef97492094901f2679c31b1756b0d87cd0883342cefedc3c95eeb75f5c

Height

#450,847

Difficulty

10.378622

Transactions

5

Size

1.22 KB

Version

2

Bits

0a60ed5b

Nonce

132,129

Timestamp

3/19/2014, 1:13:46 PM

Confirmations

6,365,827

Merkle Root

e29f8e0a54ad29273e40bed8da21127399b88e1f9cb20f41a9b50b2eaf9cf309
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.

2.238 × 10¹⁰⁰(101-digit number)
22380384313569491504…01295849247830274561
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
2.238 × 10¹⁰⁰(101-digit number)
22380384313569491504…01295849247830274561
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
4.476 × 10¹⁰⁰(101-digit number)
44760768627138983009…02591698495660549121
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
8.952 × 10¹⁰⁰(101-digit number)
89521537254277966018…05183396991321098241
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
1.790 × 10¹⁰¹(102-digit number)
17904307450855593203…10366793982642196481
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
3.580 × 10¹⁰¹(102-digit number)
35808614901711186407…20733587965284392961
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
7.161 × 10¹⁰¹(102-digit number)
71617229803422372814…41467175930568785921
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
1.432 × 10¹⁰²(103-digit number)
14323445960684474562…82934351861137571841
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
2.864 × 10¹⁰²(103-digit number)
28646891921368949125…65868703722275143681
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
5.729 × 10¹⁰²(103-digit number)
57293783842737898251…31737407444550287361
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
1.145 × 10¹⁰³(104-digit number)
11458756768547579650…63474814889100574721
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:57,777,510 XPM·at block #6,816,673 · updates every 60s
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