Block #1,078,559

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 5/27/2015, 4:01:26 PM · Difficulty 10.7609 · 5,725,223 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
bc94daa7bc0df129f585b4758c1002a0a928644b4e4952e983f33a4e766c764d

Height

#1,078,559

Difficulty

10.760855

Transactions

5

Size

1.81 KB

Version

2

Bits

0ac2c76b

Nonce

48,605,477

Timestamp

5/27/2015, 4:01:26 PM

Confirmations

5,725,223

Merkle Root

4cfe4bc913998e90b57b12c0d17bf5bcc49e016104e84686e462ee86e59f3d36
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.

1.625 × 10⁹⁷(98-digit number)
16256447936036541942…50576954039331368961
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
1.625 × 10⁹⁷(98-digit number)
16256447936036541942…50576954039331368961
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
3.251 × 10⁹⁷(98-digit number)
32512895872073083885…01153908078662737921
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
6.502 × 10⁹⁷(98-digit number)
65025791744146167770…02307816157325475841
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
1.300 × 10⁹⁸(99-digit number)
13005158348829233554…04615632314650951681
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
2.601 × 10⁹⁸(99-digit number)
26010316697658467108…09231264629301903361
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
5.202 × 10⁹⁸(99-digit number)
52020633395316934216…18462529258603806721
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
1.040 × 10⁹⁹(100-digit number)
10404126679063386843…36925058517207613441
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
2.080 × 10⁹⁹(100-digit number)
20808253358126773686…73850117034415226881
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
4.161 × 10⁹⁹(100-digit number)
41616506716253547373…47700234068830453761
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
8.323 × 10⁹⁹(100-digit number)
83233013432507094746…95400468137660907521
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:57,674,296 XPM·at block #6,803,781 · updates every 60s
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