Block #59,654

2CCLength 8★☆☆☆☆

Cunningham Chain of the Second Kind · Discovered 7/18/2013, 3:30:03 AM · Difficulty 8.9659 · 6,765,658 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
17a17da4c885612667d7220a36691a4576d6bb8a3b5517be6b0d065399ee5005

Height

#59,654

Difficulty

8.965872

Transactions

4

Size

1.29 KB

Version

2

Bits

08f7435c

Nonce

88

Timestamp

7/18/2013, 3:30:03 AM

Confirmations

6,765,658

Merkle Root

bb778b7aaf3cfb73f2ff39fef0287e07b17e8051494aac1ebe7ba752b0c10b74
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.

2.114 × 10⁹³(94-digit number)
21140719027201950363…89726262745101976701
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
2.114 × 10⁹³(94-digit number)
21140719027201950363…89726262745101976701
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
4.228 × 10⁹³(94-digit number)
42281438054403900726…79452525490203953401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
8.456 × 10⁹³(94-digit number)
84562876108807801453…58905050980407906801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
1.691 × 10⁹⁴(95-digit number)
16912575221761560290…17810101960815813601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
3.382 × 10⁹⁴(95-digit number)
33825150443523120581…35620203921631627201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
6.765 × 10⁹⁴(95-digit number)
67650300887046241162…71240407843263254401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
1.353 × 10⁹⁵(96-digit number)
13530060177409248232…42480815686526508801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
2.706 × 10⁹⁵(96-digit number)
27060120354818496465…84961631373053017601
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:57,846,599 XPM·at block #6,825,311 · updates every 60s
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