Block #449,833

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 3/18/2014, 9:07:06 PM · Difficulty 10.3721 · 6,386,860 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
83424d07b61a63f58cae50fa609ba3ebfaa5264da3550167e779c32446510dc2

Height

#449,833

Difficulty

10.372082

Transactions

1

Size

1002 B

Version

2

Bits

0a5f40c1

Nonce

75,740

Timestamp

3/18/2014, 9:07:06 PM

Confirmations

6,386,860

Merkle Root

80bf73725918a0ca10f6dfd8dd0341d4d89fdfa77c2bf29bdcc20d196c763783
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.

4.477 × 10⁹¹(92-digit number)
44770411129214802957…87769995687121366501
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
4.477 × 10⁹¹(92-digit number)
44770411129214802957…87769995687121366501
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
8.954 × 10⁹¹(92-digit number)
89540822258429605914…75539991374242733001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
1.790 × 10⁹²(93-digit number)
17908164451685921182…51079982748485466001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
3.581 × 10⁹²(93-digit number)
35816328903371842365…02159965496970932001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
7.163 × 10⁹²(93-digit number)
71632657806743684731…04319930993941864001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
1.432 × 10⁹³(94-digit number)
14326531561348736946…08639861987883728001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
2.865 × 10⁹³(94-digit number)
28653063122697473892…17279723975767456001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
5.730 × 10⁹³(94-digit number)
57306126245394947785…34559447951534912001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
1.146 × 10⁹⁴(95-digit number)
11461225249078989557…69118895903069824001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
2.292 × 10⁹⁴(95-digit number)
22922450498157979114…38237791806139648001
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:57,937,824 XPM·at block #6,836,692 · updates every 60s
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