Block #2,114,421

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 5/13/2017, 3:34:21 PM · Difficulty 10.9000 · 4,729,057 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
18e99812f3e69f189347ab165501de6cc3378e539d327b66fc62574ad9c46f46

Height

#2,114,421

Difficulty

10.899984

Transactions

2

Size

868 B

Version

2

Bits

0ae66552

Nonce

586,431,594

Timestamp

5/13/2017, 3:34:21 PM

Confirmations

4,729,057

Merkle Root

333db84f733e6e6fd6d550da1ed8159eedd0aaaa791ccaa1c21e01a84508e1d2
Transactions (2)
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.

3.745 × 10⁹³(94-digit number)
37451331151371427979…76810527507319315461
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
3.745 × 10⁹³(94-digit number)
37451331151371427979…76810527507319315461
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
7.490 × 10⁹³(94-digit number)
74902662302742855959…53621055014638630921
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
1.498 × 10⁹⁴(95-digit number)
14980532460548571191…07242110029277261841
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
2.996 × 10⁹⁴(95-digit number)
29961064921097142383…14484220058554523681
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
5.992 × 10⁹⁴(95-digit number)
59922129842194284767…28968440117109047361
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
1.198 × 10⁹⁵(96-digit number)
11984425968438856953…57936880234218094721
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
2.396 × 10⁹⁵(96-digit number)
23968851936877713907…15873760468436189441
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
4.793 × 10⁹⁵(96-digit number)
47937703873755427814…31747520936872378881
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
9.587 × 10⁹⁵(96-digit number)
95875407747510855628…63495041873744757761
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
1.917 × 10⁹⁶(97-digit number)
19175081549502171125…26990083747489515521
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:57,992,193 XPM·at block #6,843,477 · updates every 60s
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