Block #335,250

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 12/30/2013, 2:17:25 AM · Difficulty 10.1534 · 6,469,846 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
4944ca33ce2626b013a1cee4dc989d2ebe9c83693eca24aa20251cf00341aacf

Height

#335,250

Difficulty

10.153384

Transactions

9

Size

6.17 KB

Version

2

Bits

0a274425

Nonce

80,759

Timestamp

12/30/2013, 2:17:25 AM

Confirmations

6,469,846

Merkle Root

218aa55098dc582e61fd8190cbd7861e61f1fc1fe3f362b32e24e3c1f62e0816
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.

2.711 × 10¹⁰¹(102-digit number)
27116433238229955533…43693008222987072321
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
2.711 × 10¹⁰¹(102-digit number)
27116433238229955533…43693008222987072321
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
5.423 × 10¹⁰¹(102-digit number)
54232866476459911066…87386016445974144641
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
1.084 × 10¹⁰²(103-digit number)
10846573295291982213…74772032891948289281
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
2.169 × 10¹⁰²(103-digit number)
21693146590583964426…49544065783896578561
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
4.338 × 10¹⁰²(103-digit number)
43386293181167928853…99088131567793157121
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
8.677 × 10¹⁰²(103-digit number)
86772586362335857706…98176263135586314241
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
1.735 × 10¹⁰³(104-digit number)
17354517272467171541…96352526271172628481
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
3.470 × 10¹⁰³(104-digit number)
34709034544934343082…92705052542345256961
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
6.941 × 10¹⁰³(104-digit number)
69418069089868686164…85410105084690513921
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
1.388 × 10¹⁰⁴(105-digit number)
13883613817973737232…70820210169381027841
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:57,684,834 XPM·at block #6,805,095 · updates every 60s
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