Block #2,314,881

2CCLength 11★★★☆☆

Cunningham Chain of the Second Kind · Discovered 9/29/2017, 10:50:38 PM · Difficulty 10.9070 · 4,527,083 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
85f612c0cace3026fd17c24b3d228120240f5c99f683eb2ff7df658007a80719

Height

#2,314,881

Difficulty

10.906966

Transactions

2

Size

871 B

Version

2

Bits

0ae82eef

Nonce

411,469,636

Timestamp

9/29/2017, 10:50:38 PM

Confirmations

4,527,083

Merkle Root

af2207ff3add95fa34f66fe0d51f8cf1bcac398942907f366dbec55c72d9086b
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.

3.007 × 10⁹⁶(97-digit number)
30070425097739387994…55293778153049461761
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
3.007 × 10⁹⁶(97-digit number)
30070425097739387994…55293778153049461761
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
6.014 × 10⁹⁶(97-digit number)
60140850195478775988…10587556306098923521
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
1.202 × 10⁹⁷(98-digit number)
12028170039095755197…21175112612197847041
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
2.405 × 10⁹⁷(98-digit number)
24056340078191510395…42350225224395694081
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
4.811 × 10⁹⁷(98-digit number)
48112680156383020791…84700450448791388161
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
9.622 × 10⁹⁷(98-digit number)
96225360312766041582…69400900897582776321
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
1.924 × 10⁹⁸(99-digit number)
19245072062553208316…38801801795165552641
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
3.849 × 10⁹⁸(99-digit number)
38490144125106416632…77603603590331105281
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
7.698 × 10⁹⁸(99-digit number)
76980288250212833265…55207207180662210561
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
1.539 × 10⁹⁹(100-digit number)
15396057650042566653…10414414361324421121
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
11
2^10 × origin + 1
3.079 × 10⁹⁹(100-digit number)
30792115300085133306…20828828722648842241
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:57,980,094 XPM·at block #6,841,963 · updates every 60s
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