Block #437,083

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 3/10/2014, 1:22:23 AM · Difficulty 10.3591 · 6,379,124 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
09468afe884c2f2c844cde0dabc66068a527f168a929e66cd15b39c5f041b5d7

Height

#437,083

Difficulty

10.359128

Transactions

8

Size

3.77 KB

Version

2

Bits

0a5befcb

Nonce

1,388

Timestamp

3/10/2014, 1:22:23 AM

Confirmations

6,379,124

Merkle Root

f0fabbeb02d1ea49776b7a7a8b88540fe4859c62aa81c7309617313c4ebc5719
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.

1.332 × 10⁹⁷(98-digit number)
13329039749457397126…91863838452635978241
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
1.332 × 10⁹⁷(98-digit number)
13329039749457397126…91863838452635978241
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
2.665 × 10⁹⁷(98-digit number)
26658079498914794252…83727676905271956481
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
5.331 × 10⁹⁷(98-digit number)
53316158997829588504…67455353810543912961
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
1.066 × 10⁹⁸(99-digit number)
10663231799565917700…34910707621087825921
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
2.132 × 10⁹⁸(99-digit number)
21326463599131835401…69821415242175651841
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
4.265 × 10⁹⁸(99-digit number)
42652927198263670803…39642830484351303681
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
8.530 × 10⁹⁸(99-digit number)
85305854396527341607…79285660968702607361
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
1.706 × 10⁹⁹(100-digit number)
17061170879305468321…58571321937405214721
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
3.412 × 10⁹⁹(100-digit number)
34122341758610936642…17142643874810429441
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
6.824 × 10⁹⁹(100-digit number)
68244683517221873285…34285287749620858881
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:57,773,783 XPM·at block #6,816,206 · updates every 60s
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