Block #318,224

1CCLength 10★★☆☆☆

Cunningham Chain of the First Kind · Discovered 12/18/2013, 5:24:43 AM · Difficulty 10.1588 · 6,474,312 confirmations

1CC
Cunningham Chain of the First Kind

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

Block Header
Block Hash
1f25f76c3e7be99d3a3d9bdb374616d4002e44504a58042874ceccf716d020a4

Height

#318,224

Difficulty

10.158803

Transactions

8

Size

3.28 KB

Version

2

Bits

0a28a74c

Nonce

137

Timestamp

12/18/2013, 5:24:43 AM

Confirmations

6,474,312

Merkle Root

8f35ddf77a3798b9513203fea44f020ef3929fedd19b068724c536d20ea6bb3a
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.

3.298 × 10⁹²(93-digit number)
32986130625389369572…68566216723412197439
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
3.298 × 10⁹²(93-digit number)
32986130625389369572…68566216723412197439
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
2
2^1 × origin − 1
6.597 × 10⁹²(93-digit number)
65972261250778739144…37132433446824394879
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
3
2^2 × origin − 1
1.319 × 10⁹³(94-digit number)
13194452250155747828…74264866893648789759
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
4
2^3 × origin − 1
2.638 × 10⁹³(94-digit number)
26388904500311495657…48529733787297579519
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
5
2^4 × origin − 1
5.277 × 10⁹³(94-digit number)
52777809000622991315…97059467574595159039
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
6
2^5 × origin − 1
1.055 × 10⁹⁴(95-digit number)
10555561800124598263…94118935149190318079
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
7
2^6 × origin − 1
2.111 × 10⁹⁴(95-digit number)
21111123600249196526…88237870298380636159
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
8
2^7 × origin − 1
4.222 × 10⁹⁴(95-digit number)
42222247200498393052…76475740596761272319
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
9
2^8 × origin − 1
8.444 × 10⁹⁴(95-digit number)
84444494400996786104…52951481193522544639
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
10
2^9 × origin − 1
1.688 × 10⁹⁵(96-digit number)
16888898880199357220…05902962387045089279
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:57,584,257 XPM·at block #6,792,535 · updates every 60s
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