Block #529,697

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 5/7/2014, 10:08:22 AM · Difficulty 10.8904 · 6,271,636 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
a5beb37942a34f93519c1cb7e515655d3136f961ac741d77ea388b9a3dba1c43

Height

#529,697

Difficulty

10.890433

Transactions

5

Size

1.09 KB

Version

2

Bits

0ae3f365

Nonce

23,651,178

Timestamp

5/7/2014, 10:08:22 AM

Confirmations

6,271,636

Merkle Root

b72586a677d94c2e37e8b8bc69527b9f192e4a81194ec657e6d2be64fa1c1525
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.

1.591 × 10¹⁰¹(102-digit number)
15915629435818459296…56029827904969431041
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
1.591 × 10¹⁰¹(102-digit number)
15915629435818459296…56029827904969431041
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
3.183 × 10¹⁰¹(102-digit number)
31831258871636918592…12059655809938862081
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
6.366 × 10¹⁰¹(102-digit number)
63662517743273837185…24119311619877724161
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
1.273 × 10¹⁰²(103-digit number)
12732503548654767437…48238623239755448321
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
2.546 × 10¹⁰²(103-digit number)
25465007097309534874…96477246479510896641
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
5.093 × 10¹⁰²(103-digit number)
50930014194619069748…92954492959021793281
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
1.018 × 10¹⁰³(104-digit number)
10186002838923813949…85908985918043586561
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
2.037 × 10¹⁰³(104-digit number)
20372005677847627899…71817971836087173121
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
4.074 × 10¹⁰³(104-digit number)
40744011355695255798…43635943672174346241
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
8.148 × 10¹⁰³(104-digit number)
81488022711390511597…87271887344348692481
Verify on FactorDB ↗Wolfram Alpha ↗

What this block proved

The miner who found this block proved the existence of 10 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
UncommonChain length 10

Roughly 1 in 100 blocks. Solid but expected in a healthy network.

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:57,654,733 XPM·at block #6,801,332 · updates every 60s
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