Block #762,087

2CCLength 11★★★☆☆

Cunningham Chain of the Second Kind · Discovered 10/11/2014, 8:45:48 AM · Difficulty 10.9744 · 6,043,604 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
f4b9ef68b52d59b3f614860ace16678337d9daab0fe5f1f1a30487fc7acfa667

Height

#762,087

Difficulty

10.974367

Transactions

6

Size

3.04 KB

Version

2

Bits

0af97016

Nonce

348,256,565

Timestamp

10/11/2014, 8:45:48 AM

Confirmations

6,043,604

Merkle Root

d3c264cfc681a205e5c2c7937435e3b450688e259b825fd950c3bebdc1945695
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.

9.238 × 10⁹²(93-digit number)
92385610586113761682…46585688784781622601
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
9.238 × 10⁹²(93-digit number)
92385610586113761682…46585688784781622601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
1.847 × 10⁹³(94-digit number)
18477122117222752336…93171377569563245201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
3.695 × 10⁹³(94-digit number)
36954244234445504672…86342755139126490401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
7.390 × 10⁹³(94-digit number)
73908488468891009345…72685510278252980801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
1.478 × 10⁹⁴(95-digit number)
14781697693778201869…45371020556505961601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
2.956 × 10⁹⁴(95-digit number)
29563395387556403738…90742041113011923201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
5.912 × 10⁹⁴(95-digit number)
59126790775112807476…81484082226023846401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
1.182 × 10⁹⁵(96-digit number)
11825358155022561495…62968164452047692801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
2.365 × 10⁹⁵(96-digit number)
23650716310045122990…25936328904095385601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
4.730 × 10⁹⁵(96-digit number)
47301432620090245981…51872657808190771201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
11
2^10 × origin + 1
9.460 × 10⁹⁵(96-digit number)
94602865240180491962…03745315616381542401
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:57,689,610 XPM·at block #6,805,690 · updates every 60s
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