Block #529,846

2CCLength 11★★★☆☆

Cunningham Chain of the Second Kind · Discovered 5/7/2014, 12:38:03 PM · Difficulty 10.8904 · 6,279,808 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
61f91e7f3528e2387b085ffd8072fe802ba67e4d546b3eabbb42fff6682ee0eb

Height

#529,846

Difficulty

10.890411

Transactions

4

Size

2.83 KB

Version

2

Bits

0ae3f1fc

Nonce

13,038,025

Timestamp

5/7/2014, 12:38:03 PM

Confirmations

6,279,808

Merkle Root

9691ede618eb336705ff8df65312d8dad9a8cd87566d739503fc5d1e086dd46a
Transactions (4)
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.

2.177 × 10⁹⁹(100-digit number)
21771562487985907503…61030146088463164161
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
2.177 × 10⁹⁹(100-digit number)
21771562487985907503…61030146088463164161
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
4.354 × 10⁹⁹(100-digit number)
43543124975971815006…22060292176926328321
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
8.708 × 10⁹⁹(100-digit number)
87086249951943630013…44120584353852656641
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
1.741 × 10¹⁰⁰(101-digit number)
17417249990388726002…88241168707705313281
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
3.483 × 10¹⁰⁰(101-digit number)
34834499980777452005…76482337415410626561
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
6.966 × 10¹⁰⁰(101-digit number)
69668999961554904010…52964674830821253121
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
1.393 × 10¹⁰¹(102-digit number)
13933799992310980802…05929349661642506241
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
2.786 × 10¹⁰¹(102-digit number)
27867599984621961604…11858699323285012481
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
5.573 × 10¹⁰¹(102-digit number)
55735199969243923208…23717398646570024961
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
1.114 × 10¹⁰²(103-digit number)
11147039993848784641…47434797293140049921
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
11
2^10 × origin + 1
2.229 × 10¹⁰²(103-digit number)
22294079987697569283…94869594586280099841
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:57,721,313 XPM·at block #6,809,653 · updates every 60s
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