Block #337,016

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 12/31/2013, 9:16:58 AM · Difficulty 10.1382 · 6,457,438 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
bc99a8477071c13d6393715a62a8e288ce60e2a7bb218f55811fdc3cebe4777e

Height

#337,016

Difficulty

10.138241

Transactions

20

Size

12.51 KB

Version

2

Bits

0a2363c3

Nonce

223,038

Timestamp

12/31/2013, 9:16:58 AM

Confirmations

6,457,438

Merkle Root

8f4d63c908c4076ee229104666b353aa9aa3622cfe406a88d07d3a94b93ac688
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.

8.042 × 10⁹⁷(98-digit number)
80428099062103948472…86415971100262856001
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
8.042 × 10⁹⁷(98-digit number)
80428099062103948472…86415971100262856001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
1.608 × 10⁹⁸(99-digit number)
16085619812420789694…72831942200525712001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
3.217 × 10⁹⁸(99-digit number)
32171239624841579388…45663884401051424001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
6.434 × 10⁹⁸(99-digit number)
64342479249683158777…91327768802102848001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
1.286 × 10⁹⁹(100-digit number)
12868495849936631755…82655537604205696001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
2.573 × 10⁹⁹(100-digit number)
25736991699873263511…65311075208411392001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
5.147 × 10⁹⁹(100-digit number)
51473983399746527022…30622150416822784001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
1.029 × 10¹⁰⁰(101-digit number)
10294796679949305404…61244300833645568001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
2.058 × 10¹⁰⁰(101-digit number)
20589593359898610808…22488601667291136001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
4.117 × 10¹⁰⁰(101-digit number)
41179186719797221617…44977203334582272001
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:57,599,672 XPM·at block #6,794,453 · updates every 60s
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