Block #824,964

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 11/23/2014, 10:08:10 PM · Difficulty 10.9772 · 5,992,273 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
6f3495bdb30a591fd13a9e4d101b3e0467f777d457e4b6d912c3dccd2e73a049

Height

#824,964

Difficulty

10.977184

Transactions

6

Size

1.45 KB

Version

2

Bits

0afa28b9

Nonce

731,846,375

Timestamp

11/23/2014, 10:08:10 PM

Confirmations

5,992,273

Merkle Root

a37b66e19c91ca5d7054e50ce1853b14ec29b947286b21e8d45f55a3fbee042b
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.

6.972 × 10⁹⁴(95-digit number)
69721286853059528330…36116150408346506881
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
6.972 × 10⁹⁴(95-digit number)
69721286853059528330…36116150408346506881
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
1.394 × 10⁹⁵(96-digit number)
13944257370611905666…72232300816693013761
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
2.788 × 10⁹⁵(96-digit number)
27888514741223811332…44464601633386027521
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
5.577 × 10⁹⁵(96-digit number)
55777029482447622664…88929203266772055041
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
1.115 × 10⁹⁶(97-digit number)
11155405896489524532…77858406533544110081
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
2.231 × 10⁹⁶(97-digit number)
22310811792979049065…55716813067088220161
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
4.462 × 10⁹⁶(97-digit number)
44621623585958098131…11433626134176440321
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
8.924 × 10⁹⁶(97-digit number)
89243247171916196262…22867252268352880641
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
1.784 × 10⁹⁷(98-digit number)
17848649434383239252…45734504536705761281
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
3.569 × 10⁹⁷(98-digit number)
35697298868766478505…91469009073411522561
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:57,781,928 XPM·at block #6,817,236 · updates every 60s
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