Block #334,556

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 12/29/2013, 2:15:57 PM · Difficulty 10.1575 · 6,461,761 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
f2e73511a636ec84c0c9964313e3528cac965b7df0d3423e649adc0a963328b4

Height

#334,556

Difficulty

10.157499

Transactions

9

Size

3.11 KB

Version

2

Bits

0a2851d4

Nonce

4,996

Timestamp

12/29/2013, 2:15:57 PM

Confirmations

6,461,761

Merkle Root

ab133ac0c4c8288a620bb1a09129300e20b76bfba28086b7b65ba6dd9bca588b
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.

5.464 × 10⁹⁸(99-digit number)
54644601734781270327…74214284860798694401
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
5.464 × 10⁹⁸(99-digit number)
54644601734781270327…74214284860798694401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
1.092 × 10⁹⁹(100-digit number)
10928920346956254065…48428569721597388801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
2.185 × 10⁹⁹(100-digit number)
21857840693912508131…96857139443194777601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
4.371 × 10⁹⁹(100-digit number)
43715681387825016262…93714278886389555201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
8.743 × 10⁹⁹(100-digit number)
87431362775650032524…87428557772779110401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
1.748 × 10¹⁰⁰(101-digit number)
17486272555130006504…74857115545558220801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
3.497 × 10¹⁰⁰(101-digit number)
34972545110260013009…49714231091116441601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
6.994 × 10¹⁰⁰(101-digit number)
69945090220520026019…99428462182232883201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
1.398 × 10¹⁰¹(102-digit number)
13989018044104005203…98856924364465766401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
2.797 × 10¹⁰¹(102-digit number)
27978036088208010407…97713848728931532801
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:57,614,524 XPM·at block #6,796,316 · updates every 60s
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