Block #2,832,438

2CCLength 11★★★☆☆

Cunningham Chain of the Second Kind · Discovered 9/10/2018, 12:59:39 AM · Difficulty 11.7170 · 3,994,277 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
c2e187cd0cf9eead4c158309d78b09547433c9014ff82d6aa01875d614a004ef

Height

#2,832,438

Difficulty

11.716960

Transactions

8

Size

1.80 KB

Version

2

Bits

0bb78aae

Nonce

18,335,959

Timestamp

9/10/2018, 12:59:39 AM

Confirmations

3,994,277

Merkle Root

188c50b87623faeb86963fe04f5a66183880a549aaf5d5e809de0929719af4f1
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.

3.512 × 10⁹⁶(97-digit number)
35125920739270808487…70812059272135198081
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
3.512 × 10⁹⁶(97-digit number)
35125920739270808487…70812059272135198081
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
7.025 × 10⁹⁶(97-digit number)
70251841478541616975…41624118544270396161
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
1.405 × 10⁹⁷(98-digit number)
14050368295708323395…83248237088540792321
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
2.810 × 10⁹⁷(98-digit number)
28100736591416646790…66496474177081584641
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
5.620 × 10⁹⁷(98-digit number)
56201473182833293580…32992948354163169281
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
1.124 × 10⁹⁸(99-digit number)
11240294636566658716…65985896708326338561
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
2.248 × 10⁹⁸(99-digit number)
22480589273133317432…31971793416652677121
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
4.496 × 10⁹⁸(99-digit number)
44961178546266634864…63943586833305354241
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
8.992 × 10⁹⁸(99-digit number)
89922357092533269728…27887173666610708481
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
1.798 × 10⁹⁹(100-digit number)
17984471418506653945…55774347333221416961
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
11
2^10 × origin + 1
3.596 × 10⁹⁹(100-digit number)
35968942837013307891…11548694666442833921
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:57,857,873 XPM·at block #6,826,714 · updates every 60s
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