Block #324,402

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 12/22/2013, 7:39:15 AM · Difficulty 10.2066 · 6,485,293 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
449356cfcb8813db6728f2d17fc88e9bc3c5f307d2faa1a40bced62b13e63849

Height

#324,402

Difficulty

10.206603

Transactions

10

Size

2.62 KB

Version

2

Bits

0a34e3ec

Nonce

290,214

Timestamp

12/22/2013, 7:39:15 AM

Confirmations

6,485,293

Merkle Root

c0bf4684d4e378b1567b8bbe5fbd9618f3ff8cdfb21e253e60537c8c04a14e12
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.

2.468 × 10¹⁰²(103-digit number)
24687642652556467889…65408063770848363521
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
2.468 × 10¹⁰²(103-digit number)
24687642652556467889…65408063770848363521
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
4.937 × 10¹⁰²(103-digit number)
49375285305112935779…30816127541696727041
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
9.875 × 10¹⁰²(103-digit number)
98750570610225871558…61632255083393454081
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
1.975 × 10¹⁰³(104-digit number)
19750114122045174311…23264510166786908161
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
3.950 × 10¹⁰³(104-digit number)
39500228244090348623…46529020333573816321
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
7.900 × 10¹⁰³(104-digit number)
79000456488180697246…93058040667147632641
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
1.580 × 10¹⁰⁴(105-digit number)
15800091297636139449…86116081334295265281
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
3.160 × 10¹⁰⁴(105-digit number)
31600182595272278898…72232162668590530561
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
6.320 × 10¹⁰⁴(105-digit number)
63200365190544557797…44464325337181061121
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
1.264 × 10¹⁰⁵(106-digit number)
12640073038108911559…88928650674362122241
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:57,721,637 XPM·at block #6,809,694 · updates every 60s
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