Block #2,297,108

2CCLength 11★★★☆☆

Cunningham Chain of the Second Kind · Discovered 9/15/2017, 12:33:57 PM · Difficulty 10.9484 · 4,539,749 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
da6e33f9b1c2904a5010f388445232a2c9e823ff76d15ec10ced9fc23b31a665

Height

#2,297,108

Difficulty

10.948364

Transactions

2

Size

574 B

Version

2

Bits

0af2c7ff

Nonce

985,885,657

Timestamp

9/15/2017, 12:33:57 PM

Confirmations

4,539,749

Merkle Root

155a1ac09185848885dde188ef8e48b008ed294f9a3c77cf046cb26368a45acd
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.

2.062 × 10⁹³(94-digit number)
20624471367547845736…79221172720971507041
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
2.062 × 10⁹³(94-digit number)
20624471367547845736…79221172720971507041
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
4.124 × 10⁹³(94-digit number)
41248942735095691472…58442345441943014081
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
8.249 × 10⁹³(94-digit number)
82497885470191382944…16884690883886028161
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
1.649 × 10⁹⁴(95-digit number)
16499577094038276588…33769381767772056321
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
3.299 × 10⁹⁴(95-digit number)
32999154188076553177…67538763535544112641
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
6.599 × 10⁹⁴(95-digit number)
65998308376153106355…35077527071088225281
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
1.319 × 10⁹⁵(96-digit number)
13199661675230621271…70155054142176450561
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
2.639 × 10⁹⁵(96-digit number)
26399323350461242542…40310108284352901121
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
5.279 × 10⁹⁵(96-digit number)
52798646700922485084…80620216568705802241
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
1.055 × 10⁹⁶(97-digit number)
10559729340184497016…61240433137411604481
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
11
2^10 × origin + 1
2.111 × 10⁹⁶(97-digit number)
21119458680368994033…22480866274823208961
Verify on FactorDB ↗Wolfram Alpha ↗

What this block proved

The miner who found this block proved the existence of 11 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
RareChain length 11

Approximately 1 in 1,000 blocks. Noteworthy discoveries.

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:57,939,145 XPM·at block #6,836,856 · updates every 60s
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