Block #361,234

2CCLength 11★★★☆☆

Cunningham Chain of the Second Kind · Discovered 1/15/2014, 10:55:41 PM · Difficulty 10.4052 · 6,453,081 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
72f2535096808676220bfc9948d5ab53e1ecb5cd63cf249f16e3b2caf8ddb593

Height

#361,234

Difficulty

10.405172

Transactions

4

Size

1.00 KB

Version

2

Bits

0a67b953

Nonce

53,488

Timestamp

1/15/2014, 10:55:41 PM

Confirmations

6,453,081

Merkle Root

73d4d3f4cdef5f743df9e0b4f2e98540a4ad1757479e74e4bb8080f6bd0efade
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.

1.851 × 10⁹³(94-digit number)
18514444761349721863…64720846607358982401
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
1.851 × 10⁹³(94-digit number)
18514444761349721863…64720846607358982401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
3.702 × 10⁹³(94-digit number)
37028889522699443727…29441693214717964801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
7.405 × 10⁹³(94-digit number)
74057779045398887454…58883386429435929601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
1.481 × 10⁹⁴(95-digit number)
14811555809079777490…17766772858871859201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
2.962 × 10⁹⁴(95-digit number)
29623111618159554981…35533545717743718401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
5.924 × 10⁹⁴(95-digit number)
59246223236319109963…71067091435487436801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
1.184 × 10⁹⁵(96-digit number)
11849244647263821992…42134182870974873601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
2.369 × 10⁹⁵(96-digit number)
23698489294527643985…84268365741949747201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
4.739 × 10⁹⁵(96-digit number)
47396978589055287971…68536731483899494401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
9.479 × 10⁹⁵(96-digit number)
94793957178110575942…37073462967798988801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
11
2^10 × origin + 1
1.895 × 10⁹⁶(97-digit number)
18958791435622115188…74146925935597977601
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:57,758,583 XPM·at block #6,814,314 · updates every 60s
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