Block #2,733,598

2CCLength 11★★★☆☆

Cunningham Chain of the Second Kind · Discovered 7/4/2018, 8:33:58 AM · Difficulty 11.6244 · 4,108,067 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
922aacc6ed9c701ca4b5eb1c942071b21b14691f7a569e528326f77ced5301a0

Height

#2,733,598

Difficulty

11.624350

Transactions

6

Size

1.52 KB

Version

2

Bits

0b9fd56d

Nonce

12,915,292

Timestamp

7/4/2018, 8:33:58 AM

Confirmations

4,108,067

Merkle Root

58f6d351ebbc2cf3b5f9942b43a0bb26a6f68f754c775ec73fdd0d4ef015d18e
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.

1.720 × 10⁹⁴(95-digit number)
17202702380000275035…50202363934607338001
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
1.720 × 10⁹⁴(95-digit number)
17202702380000275035…50202363934607338001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
3.440 × 10⁹⁴(95-digit number)
34405404760000550071…00404727869214676001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
6.881 × 10⁹⁴(95-digit number)
68810809520001100142…00809455738429352001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
1.376 × 10⁹⁵(96-digit number)
13762161904000220028…01618911476858704001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
2.752 × 10⁹⁵(96-digit number)
27524323808000440056…03237822953717408001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
5.504 × 10⁹⁵(96-digit number)
55048647616000880113…06475645907434816001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
1.100 × 10⁹⁶(97-digit number)
11009729523200176022…12951291814869632001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
2.201 × 10⁹⁶(97-digit number)
22019459046400352045…25902583629739264001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
4.403 × 10⁹⁶(97-digit number)
44038918092800704091…51805167259478528001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
8.807 × 10⁹⁶(97-digit number)
88077836185601408182…03610334518957056001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
11
2^10 × origin + 1
1.761 × 10⁹⁷(98-digit number)
17615567237120281636…07220669037914112001
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:57,977,709 XPM·at block #6,841,664 · updates every 60s
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