Block #701,135

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 8/31/2014, 11:04:59 AM · Difficulty 10.9591 · 6,126,023 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
ef6c9faf2df46e830f72365510824ae0b68b671aad601e5ea27d01e4fa42521b

Height

#701,135

Difficulty

10.959086

Transactions

2

Size

798 B

Version

2

Bits

0af586a3

Nonce

1,146,511,505

Timestamp

8/31/2014, 11:04:59 AM

Confirmations

6,126,023

Merkle Root

424de17c780c8c7ae80799f680ce746643870f8e657a8c9037c667a6fb405c93
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.

1.114 × 10⁹⁶(97-digit number)
11146975052203791544…63936941019000332801
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
1.114 × 10⁹⁶(97-digit number)
11146975052203791544…63936941019000332801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
2.229 × 10⁹⁶(97-digit number)
22293950104407583088…27873882038000665601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
4.458 × 10⁹⁶(97-digit number)
44587900208815166177…55747764076001331201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
8.917 × 10⁹⁶(97-digit number)
89175800417630332354…11495528152002662401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
1.783 × 10⁹⁷(98-digit number)
17835160083526066470…22991056304005324801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
3.567 × 10⁹⁷(98-digit number)
35670320167052132941…45982112608010649601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
7.134 × 10⁹⁷(98-digit number)
71340640334104265883…91964225216021299201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
1.426 × 10⁹⁸(99-digit number)
14268128066820853176…83928450432042598401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
2.853 × 10⁹⁸(99-digit number)
28536256133641706353…67856900864085196801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
5.707 × 10⁹⁸(99-digit number)
57072512267283412707…35713801728170393601
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:57,861,448 XPM·at block #6,827,157 · updates every 60s
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