Block #2,179,814

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 6/26/2017, 8:38:50 PM · Difficulty 10.9306 · 4,657,813 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
ba2b8fa582ed2f5f6ae8a6cedf481739ba054fd977821b1a89b31e323301e998

Height

#2,179,814

Difficulty

10.930580

Transactions

2

Size

425 B

Version

2

Bits

0aee3a86

Nonce

716,281,490

Timestamp

6/26/2017, 8:38:50 PM

Confirmations

4,657,813

Merkle Root

b05acdfad3d2175d97d47669e7b9607b2f3ad5fc36255177d46131ceffeecd2d
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.

1.886 × 10⁹⁶(97-digit number)
18867805167679545725…89868634410272317441
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
1.886 × 10⁹⁶(97-digit number)
18867805167679545725…89868634410272317441
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
3.773 × 10⁹⁶(97-digit number)
37735610335359091450…79737268820544634881
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
7.547 × 10⁹⁶(97-digit number)
75471220670718182901…59474537641089269761
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
1.509 × 10⁹⁷(98-digit number)
15094244134143636580…18949075282178539521
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
3.018 × 10⁹⁷(98-digit number)
30188488268287273160…37898150564357079041
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
6.037 × 10⁹⁷(98-digit number)
60376976536574546321…75796301128714158081
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
1.207 × 10⁹⁸(99-digit number)
12075395307314909264…51592602257428316161
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
2.415 × 10⁹⁸(99-digit number)
24150790614629818528…03185204514856632321
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
4.830 × 10⁹⁸(99-digit number)
48301581229259637057…06370409029713264641
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
9.660 × 10⁹⁸(99-digit number)
96603162458519274114…12740818059426529281
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:57,945,340 XPM·at block #6,837,626 · updates every 60s
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