Block #57,734

2CCLength 9★☆☆☆☆

Cunningham Chain of the Second Kind · Discovered 7/17/2013, 4:34:53 PM · Difficulty 8.9561 · 6,747,935 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
85953820bb741c2dca3b1ef736faec34cab92befd9e3759635a92d51653b7de2

Height

#57,734

Difficulty

8.956084

Transactions

7

Size

1.82 KB

Version

2

Bits

08f4c1e8

Nonce

6

Timestamp

7/17/2013, 4:34:53 PM

Confirmations

6,747,935

Merkle Root

a22a1f95cb9aa95e672b3fb26244876d35d0d7297eea8d01d8a6908c88b939d6
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.

1.794 × 10⁹²(93-digit number)
17946411764842931715…49628914156750046401
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
1.794 × 10⁹²(93-digit number)
17946411764842931715…49628914156750046401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
3.589 × 10⁹²(93-digit number)
35892823529685863430…99257828313500092801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
7.178 × 10⁹²(93-digit number)
71785647059371726860…98515656627000185601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
1.435 × 10⁹³(94-digit number)
14357129411874345372…97031313254000371201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
2.871 × 10⁹³(94-digit number)
28714258823748690744…94062626508000742401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
5.742 × 10⁹³(94-digit number)
57428517647497381488…88125253016001484801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
1.148 × 10⁹⁴(95-digit number)
11485703529499476297…76250506032002969601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
2.297 × 10⁹⁴(95-digit number)
22971407058998952595…52501012064005939201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
4.594 × 10⁹⁴(95-digit number)
45942814117997905190…05002024128011878401
Verify on FactorDB ↗Wolfram Alpha ↗

What this block proved

The miner who found this block proved the existence of 9 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 9

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:57,689,430 XPM·at block #6,805,668 · updates every 60s
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