Block #333,755

2CCLength 11★★★☆☆

Cunningham Chain of the Second Kind · Discovered 12/29/2013, 12:35:21 AM · Difficulty 10.1603 · 6,462,850 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
7ff7fd1b0a02957a8624df2d7fd6535f4abab8703ce4264138dbf8ca6b9c244c

Height

#333,755

Difficulty

10.160320

Transactions

5

Size

1.95 KB

Version

2

Bits

0a290ac3

Nonce

16,342

Timestamp

12/29/2013, 12:35:21 AM

Confirmations

6,462,850

Merkle Root

530da61d88cd301697f3e6d8691b4ad5ae4d33e7cd08ce4cbe08244c7bc90607
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.

7.203 × 10⁹³(94-digit number)
72035803461257770974…38990045546687926241
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
7.203 × 10⁹³(94-digit number)
72035803461257770974…38990045546687926241
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
1.440 × 10⁹⁴(95-digit number)
14407160692251554194…77980091093375852481
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
2.881 × 10⁹⁴(95-digit number)
28814321384503108389…55960182186751704961
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
5.762 × 10⁹⁴(95-digit number)
57628642769006216779…11920364373503409921
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
1.152 × 10⁹⁵(96-digit number)
11525728553801243355…23840728747006819841
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
2.305 × 10⁹⁵(96-digit number)
23051457107602486711…47681457494013639681
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
4.610 × 10⁹⁵(96-digit number)
46102914215204973423…95362914988027279361
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
9.220 × 10⁹⁵(96-digit number)
92205828430409946847…90725829976054558721
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
1.844 × 10⁹⁶(97-digit number)
18441165686081989369…81451659952109117441
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
3.688 × 10⁹⁶(97-digit number)
36882331372163978738…62903319904218234881
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
11
2^10 × origin + 1
7.376 × 10⁹⁶(97-digit number)
73764662744327957477…25806639808436469761
Verify on FactorDB ↗Wolfram Alpha ↗

What this block proved

The miner who found this block proved the existence of 11 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
RareChain length 11

Approximately 1 in 1,000 blocks. Noteworthy discoveries.

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:57,616,843 XPM·at block #6,796,604 · updates every 60s
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