Block #324,407

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 12/22/2013, 7:43:25 AM · Difficulty 10.2067 · 6,493,472 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
f63b85046e37eebe1eba8f5f5398ece7fe52f758b1f0e7a8a0d1c2ef2cb30313

Height

#324,407

Difficulty

10.206737

Transactions

4

Size

2.11 KB

Version

2

Bits

0a34ecb3

Nonce

88,088

Timestamp

12/22/2013, 7:43:25 AM

Confirmations

6,493,472

Merkle Root

ae585e3667052ea255b0595c84793e015247a6f71b5601c8ebb0e52fd09dd447
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.

9.822 × 10⁹³(94-digit number)
98227809663066934209…62850365995500482561
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
9.822 × 10⁹³(94-digit number)
98227809663066934209…62850365995500482561
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
1.964 × 10⁹⁴(95-digit number)
19645561932613386841…25700731991000965121
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
3.929 × 10⁹⁴(95-digit number)
39291123865226773683…51401463982001930241
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
7.858 × 10⁹⁴(95-digit number)
78582247730453547367…02802927964003860481
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
1.571 × 10⁹⁵(96-digit number)
15716449546090709473…05605855928007720961
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
3.143 × 10⁹⁵(96-digit number)
31432899092181418947…11211711856015441921
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
6.286 × 10⁹⁵(96-digit number)
62865798184362837894…22423423712030883841
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
1.257 × 10⁹⁶(97-digit number)
12573159636872567578…44846847424061767681
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
2.514 × 10⁹⁶(97-digit number)
25146319273745135157…89693694848123535361
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
5.029 × 10⁹⁶(97-digit number)
50292638547490270315…79387389696247070721
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:57,787,092 XPM·at block #6,817,878 · updates every 60s
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