Block #460,401

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 3/25/2014, 11:56:35 PM · Difficulty 10.4177 · 6,349,112 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
1fb6b295a56bb4720b4463fb3914fac6b9cc31068a4c43aec31f04db284559b8

Height

#460,401

Difficulty

10.417681

Transactions

2

Size

1.65 KB

Version

2

Bits

0a6aed1f

Nonce

27,617

Timestamp

3/25/2014, 11:56:35 PM

Confirmations

6,349,112

Merkle Root

6964cad2fad0b51a6cd515109048ce94ee0197e93561e0508b731c7e82d9697f
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.

6.561 × 10⁹⁴(95-digit number)
65618435733567544635…55918070089839889281
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
6.561 × 10⁹⁴(95-digit number)
65618435733567544635…55918070089839889281
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
1.312 × 10⁹⁵(96-digit number)
13123687146713508927…11836140179679778561
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
2.624 × 10⁹⁵(96-digit number)
26247374293427017854…23672280359359557121
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
5.249 × 10⁹⁵(96-digit number)
52494748586854035708…47344560718719114241
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
1.049 × 10⁹⁶(97-digit number)
10498949717370807141…94689121437438228481
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
2.099 × 10⁹⁶(97-digit number)
20997899434741614283…89378242874876456961
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
4.199 × 10⁹⁶(97-digit number)
41995798869483228566…78756485749752913921
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
8.399 × 10⁹⁶(97-digit number)
83991597738966457133…57512971499505827841
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
1.679 × 10⁹⁷(98-digit number)
16798319547793291426…15025942999011655681
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
3.359 × 10⁹⁷(98-digit number)
33596639095586582853…30051885998023311361
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:57,720,179 XPM·at block #6,809,512 · updates every 60s
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