Block #2,833,095

2CCLength 11★★★☆☆

Cunningham Chain of the Second Kind · Discovered 9/10/2018, 12:37:56 PM · Difficulty 11.7146 · 4,012,269 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
5df2934de4a44dfb15b569339e31ad18f422927cc2d966e518dbb49ce94e62ac

Height

#2,833,095

Difficulty

11.714591

Transactions

2

Size

426 B

Version

2

Bits

0bb6ef6c

Nonce

468,574,934

Timestamp

9/10/2018, 12:37:56 PM

Confirmations

4,012,269

Merkle Root

6b6df04768a20af0214297c53a57c97b4748b8aa68746959cdce1da119362563
Transactions (2)
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.

2.089 × 10⁹⁴(95-digit number)
20890948104973195803…46188388378902746001
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
2.089 × 10⁹⁴(95-digit number)
20890948104973195803…46188388378902746001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
4.178 × 10⁹⁴(95-digit number)
41781896209946391607…92376776757805492001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
8.356 × 10⁹⁴(95-digit number)
83563792419892783215…84753553515610984001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
1.671 × 10⁹⁵(96-digit number)
16712758483978556643…69507107031221968001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
3.342 × 10⁹⁵(96-digit number)
33425516967957113286…39014214062443936001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
6.685 × 10⁹⁵(96-digit number)
66851033935914226572…78028428124887872001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
1.337 × 10⁹⁶(97-digit number)
13370206787182845314…56056856249775744001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
2.674 × 10⁹⁶(97-digit number)
26740413574365690629…12113712499551488001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
5.348 × 10⁹⁶(97-digit number)
53480827148731381258…24227424999102976001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
1.069 × 10⁹⁷(98-digit number)
10696165429746276251…48454849998205952001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
11
2^10 × origin + 1
2.139 × 10⁹⁷(98-digit number)
21392330859492552503…96909699996411904001
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:58,007,356 XPM·at block #6,845,363 · updates every 60s
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