Block #2,799,437

2CCLength 11★★★☆☆

Cunningham Chain of the Second Kind · Discovered 8/18/2018, 2:03:45 PM · Difficulty 11.6758 · 4,042,100 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
40a21261bd423d5e53d51b212015e6bec2baeddae71bd0bb35f0e34f9e9673a9

Height

#2,799,437

Difficulty

11.675842

Transactions

35

Size

8.57 KB

Version

2

Bits

0bad0402

Nonce

152,777,306

Timestamp

8/18/2018, 2:03:45 PM

Confirmations

4,042,100

Merkle Root

c5993b7565ac88567390650cf9c81da998b413eb91c687cd55d1ca8a81d72788
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.

3.260 × 10⁹⁴(95-digit number)
32609086941206489329…29372715391900174401
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
3.260 × 10⁹⁴(95-digit number)
32609086941206489329…29372715391900174401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
6.521 × 10⁹⁴(95-digit number)
65218173882412978659…58745430783800348801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
1.304 × 10⁹⁵(96-digit number)
13043634776482595731…17490861567600697601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
2.608 × 10⁹⁵(96-digit number)
26087269552965191463…34981723135201395201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
5.217 × 10⁹⁵(96-digit number)
52174539105930382927…69963446270402790401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
1.043 × 10⁹⁶(97-digit number)
10434907821186076585…39926892540805580801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
2.086 × 10⁹⁶(97-digit number)
20869815642372153171…79853785081611161601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
4.173 × 10⁹⁶(97-digit number)
41739631284744306342…59707570163222323201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
8.347 × 10⁹⁶(97-digit number)
83479262569488612684…19415140326444646401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
1.669 × 10⁹⁷(98-digit number)
16695852513897722536…38830280652889292801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
11
2^10 × origin + 1
3.339 × 10⁹⁷(98-digit number)
33391705027795445073…77660561305778585601
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:57,976,679 XPM·at block #6,841,536 · updates every 60s
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