Block #359,951

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 1/15/2014, 3:37:25 AM · Difficulty 10.3881 · 6,449,817 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
2fdb3782c69e7276f13496ffbb34e24dfac95d5d669278e08a4b029a69f67156

Height

#359,951

Difficulty

10.388055

Transactions

10

Size

2.75 KB

Version

2

Bits

0a635792

Nonce

29,441

Timestamp

1/15/2014, 3:37:25 AM

Confirmations

6,449,817

Merkle Root

c8a24da6cf40ae92ea3cb83f10be7ee4caf49837499d49df08234d1b101cebf4
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.

6.800 × 10⁹²(93-digit number)
68004019130565477195…00097680145689039451
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
6.800 × 10⁹²(93-digit number)
68004019130565477195…00097680145689039451
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
1.360 × 10⁹³(94-digit number)
13600803826113095439…00195360291378078901
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
2.720 × 10⁹³(94-digit number)
27201607652226190878…00390720582756157801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
5.440 × 10⁹³(94-digit number)
54403215304452381756…00781441165512315601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
1.088 × 10⁹⁴(95-digit number)
10880643060890476351…01562882331024631201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
2.176 × 10⁹⁴(95-digit number)
21761286121780952702…03125764662049262401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
4.352 × 10⁹⁴(95-digit number)
43522572243561905405…06251529324098524801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
8.704 × 10⁹⁴(95-digit number)
87045144487123810810…12503058648197049601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
1.740 × 10⁹⁵(96-digit number)
17409028897424762162…25006117296394099201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
3.481 × 10⁹⁵(96-digit number)
34818057794849524324…50012234592788198401
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:57,722,231 XPM·at block #6,809,767 · updates every 60s
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