Block #58,723

2CCLength 8★☆☆☆☆

Cunningham Chain of the Second Kind · Discovered 7/17/2013, 10:16:35 PM · Difficulty 8.9614 · 6,736,881 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
c98fdca654e51817ceb5d6f4b8d69a75a480a7be6c1183f575a11bea60e06ff6

Height

#58,723

Difficulty

8.961390

Transactions

10

Size

2.61 KB

Version

2

Bits

08f61dac

Nonce

275

Timestamp

7/17/2013, 10:16:35 PM

Confirmations

6,736,881

Merkle Root

5a3011444e39804674fa3c7e2c454a0fc6c2c8857a451abaa1277003f54666b5
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.

5.579 × 10⁸⁵(86-digit number)
55794890058033575033…28394500953528687201
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
5.579 × 10⁸⁵(86-digit number)
55794890058033575033…28394500953528687201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
1.115 × 10⁸⁶(87-digit number)
11158978011606715006…56789001907057374401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
2.231 × 10⁸⁶(87-digit number)
22317956023213430013…13578003814114748801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
4.463 × 10⁸⁶(87-digit number)
44635912046426860026…27156007628229497601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
8.927 × 10⁸⁶(87-digit number)
89271824092853720052…54312015256458995201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
1.785 × 10⁸⁷(88-digit number)
17854364818570744010…08624030512917990401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
3.570 × 10⁸⁷(88-digit number)
35708729637141488021…17248061025835980801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
7.141 × 10⁸⁷(88-digit number)
71417459274282976042…34496122051671961601
Verify on FactorDB ↗Wolfram Alpha ↗

What this block proved

The miner who found this block proved the existence of 8 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
CommonChain length 8

Found in most blocks. The baseline for Primecoin's proof-of-work.

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:57,608,895 XPM·at block #6,795,603 · updates every 60s
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