Block #324,323

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 12/22/2013, 6:19:49 AM · Difficulty 10.2071 · 6,481,588 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
bddac168820f450377c40b61646a107f0e1b49f0f1c6cc6233bfd047684bc10e

Height

#324,323

Difficulty

10.207087

Transactions

26

Size

8.49 KB

Version

2

Bits

0a3503aa

Nonce

32,365

Timestamp

12/22/2013, 6:19:49 AM

Confirmations

6,481,588

Merkle Root

7280d05916e1fccc70faac4e03b77dee414aebb3d90f1c839f7a6e4780af137f
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.

2.855 × 10¹⁰⁰(101-digit number)
28553955571824593328…28706717748825337601
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
2.855 × 10¹⁰⁰(101-digit number)
28553955571824593328…28706717748825337601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
5.710 × 10¹⁰⁰(101-digit number)
57107911143649186657…57413435497650675201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
1.142 × 10¹⁰¹(102-digit number)
11421582228729837331…14826870995301350401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
2.284 × 10¹⁰¹(102-digit number)
22843164457459674663…29653741990602700801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
4.568 × 10¹⁰¹(102-digit number)
45686328914919349326…59307483981205401601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
9.137 × 10¹⁰¹(102-digit number)
91372657829838698652…18614967962410803201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
1.827 × 10¹⁰²(103-digit number)
18274531565967739730…37229935924821606401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
3.654 × 10¹⁰²(103-digit number)
36549063131935479461…74459871849643212801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
7.309 × 10¹⁰²(103-digit number)
73098126263870958922…48919743699286425601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
1.461 × 10¹⁰³(104-digit number)
14619625252774191784…97839487398572851201
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:57,691,377 XPM·at block #6,805,910 · updates every 60s
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