Block #226,986

1CCLength 10★★☆☆☆

Cunningham Chain of the First Kind · Discovered 10/25/2013, 2:25:56 PM · Difficulty 9.9362 · 6,569,209 confirmations

1CC
Cunningham Chain of the First Kind

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

Block Header
Block Hash
91eb6d91f50a84dd6992c84e6976d47f1bc22c9abe3d7cee42a5e40e71eb8487

Height

#226,986

Difficulty

9.936170

Transactions

12

Size

7.96 KB

Version

2

Bits

09efa8d9

Nonce

184,991

Timestamp

10/25/2013, 2:25:56 PM

Confirmations

6,569,209

Merkle Root

118949c9681be2836ce636cb9c0a0a98a4d98e381f51d9c985e4847c03fa2f7a
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.

2.639 × 10⁹²(93-digit number)
26396941252958357985…88946880006409088919
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
2.639 × 10⁹²(93-digit number)
26396941252958357985…88946880006409088919
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
2
2^1 × origin − 1
5.279 × 10⁹²(93-digit number)
52793882505916715971…77893760012818177839
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
3
2^2 × origin − 1
1.055 × 10⁹³(94-digit number)
10558776501183343194…55787520025636355679
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
4
2^3 × origin − 1
2.111 × 10⁹³(94-digit number)
21117553002366686388…11575040051272711359
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
5
2^4 × origin − 1
4.223 × 10⁹³(94-digit number)
42235106004733372776…23150080102545422719
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
6
2^5 × origin − 1
8.447 × 10⁹³(94-digit number)
84470212009466745553…46300160205090845439
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
7
2^6 × origin − 1
1.689 × 10⁹⁴(95-digit number)
16894042401893349110…92600320410181690879
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
8
2^7 × origin − 1
3.378 × 10⁹⁴(95-digit number)
33788084803786698221…85200640820363381759
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
9
2^8 × origin − 1
6.757 × 10⁹⁴(95-digit number)
67576169607573396442…70401281640726763519
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
10
2^9 × origin − 1
1.351 × 10⁹⁵(96-digit number)
13515233921514679288…40802563281453527039
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 First 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 1CC formula:

1CC: p₁ (first prime), p₂ = 2p₁ + 1, p₃ = 2p₂ + 1, …
Circulating Supply:57,613,560 XPM·at block #6,796,194 · updates every 60s
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