Block #2,110,693

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 5/10/2017, 10:37:18 PM · Difficulty 10.9031 · 4,731,662 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
b2c13d763e5f962468dd1c9225ca2d0bca2367f3ad69c3591231bfc6d02f0f19

Height

#2,110,693

Difficulty

10.903147

Transactions

5

Size

1.37 KB

Version

2

Bits

0ae734a2

Nonce

1,200,168,150

Timestamp

5/10/2017, 10:37:18 PM

Confirmations

4,731,662

Merkle Root

2bdb589d64ca0512207402bccc9024bbd82add0ce3aecac8e70322faf1c5ee0c
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.

1.424 × 10⁹⁴(95-digit number)
14241900467738314558…42339935606422729761
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
1.424 × 10⁹⁴(95-digit number)
14241900467738314558…42339935606422729761
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
2.848 × 10⁹⁴(95-digit number)
28483800935476629116…84679871212845459521
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
5.696 × 10⁹⁴(95-digit number)
56967601870953258232…69359742425690919041
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
1.139 × 10⁹⁵(96-digit number)
11393520374190651646…38719484851381838081
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
2.278 × 10⁹⁵(96-digit number)
22787040748381303293…77438969702763676161
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
4.557 × 10⁹⁵(96-digit number)
45574081496762606586…54877939405527352321
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
9.114 × 10⁹⁵(96-digit number)
91148162993525213172…09755878811054704641
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
1.822 × 10⁹⁶(97-digit number)
18229632598705042634…19511757622109409281
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
3.645 × 10⁹⁶(97-digit number)
36459265197410085269…39023515244218818561
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
7.291 × 10⁹⁶(97-digit number)
72918530394820170538…78047030488437637121
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:57,983,247 XPM·at block #6,842,354 · updates every 60s
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