Block #3,284,074

2CCLength 11★★★☆☆

Cunningham Chain of the Second Kind · Discovered 7/27/2019, 5:13:57 PM · Difficulty 10.9948 · 3,517,129 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
d3576f0848a2e01bb2290cb48a8a348759f3f999b5774d99a46fa3da143134fd

Height

#3,284,074

Difficulty

10.994809

Transactions

5

Size

1.27 KB

Version

2

Bits

0afeabca

Nonce

149,622,873

Timestamp

7/27/2019, 5:13:57 PM

Confirmations

3,517,129

Merkle Root

ff296e47063fb73246bf4f424eb7bc741345ec91a7e3e1accf707f7de1699217
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.

3.377 × 10⁹⁴(95-digit number)
33774530417942827441…88919289699736696321
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
3.377 × 10⁹⁴(95-digit number)
33774530417942827441…88919289699736696321
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
6.754 × 10⁹⁴(95-digit number)
67549060835885654883…77838579399473392641
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
1.350 × 10⁹⁵(96-digit number)
13509812167177130976…55677158798946785281
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
2.701 × 10⁹⁵(96-digit number)
27019624334354261953…11354317597893570561
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
5.403 × 10⁹⁵(96-digit number)
54039248668708523907…22708635195787141121
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
1.080 × 10⁹⁶(97-digit number)
10807849733741704781…45417270391574282241
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
2.161 × 10⁹⁶(97-digit number)
21615699467483409562…90834540783148564481
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
4.323 × 10⁹⁶(97-digit number)
43231398934966819125…81669081566297128961
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
8.646 × 10⁹⁶(97-digit number)
86462797869933638251…63338163132594257921
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
1.729 × 10⁹⁷(98-digit number)
17292559573986727650…26676326265188515841
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
11
2^10 × origin + 1
3.458 × 10⁹⁷(98-digit number)
34585119147973455300…53352652530377031681
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:57,653,688 XPM·at block #6,801,202 · updates every 60s
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