Block #3,514,792

2CCLength 11★★★☆☆

Cunningham Chain of the Second Kind · Discovered 1/15/2020, 1:22:12 AM · Difficulty 10.9322 · 3,325,544 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
7ba3d25e0348743f23b6ea48f1444b6eee32bd58bdf364c2bd30566f6245432b

Height

#3,514,792

Difficulty

10.932177

Transactions

12

Size

4.34 KB

Version

2

Bits

0aeea32a

Nonce

716,429,927

Timestamp

1/15/2020, 1:22:12 AM

Confirmations

3,325,544

Merkle Root

82a85c353622732c9dfead3dbdf91c8602f7b2713ea128d09c01531f5d793a3d
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.

3.732 × 10⁹³(94-digit number)
37326152071151527309…70869551656300420001
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
3.732 × 10⁹³(94-digit number)
37326152071151527309…70869551656300420001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
7.465 × 10⁹³(94-digit number)
74652304142303054618…41739103312600840001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
1.493 × 10⁹⁴(95-digit number)
14930460828460610923…83478206625201680001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
2.986 × 10⁹⁴(95-digit number)
29860921656921221847…66956413250403360001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
5.972 × 10⁹⁴(95-digit number)
59721843313842443694…33912826500806720001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
1.194 × 10⁹⁵(96-digit number)
11944368662768488738…67825653001613440001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
2.388 × 10⁹⁵(96-digit number)
23888737325536977477…35651306003226880001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
4.777 × 10⁹⁵(96-digit number)
47777474651073954955…71302612006453760001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
9.555 × 10⁹⁵(96-digit number)
95554949302147909911…42605224012907520001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
1.911 × 10⁹⁶(97-digit number)
19110989860429581982…85210448025815040001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
11
2^10 × origin + 1
3.822 × 10⁹⁶(97-digit number)
38221979720859163964…70420896051630080001
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:57,967,009 XPM·at block #6,840,335 · updates every 60s
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