Block #314,181

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 12/15/2013, 8:18:19 PM · Difficulty 10.0485 · 6,499,723 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
0fa7cfca77a7414edd14d6de3cfdda015e8716bb5f1315e39b2de42f6282ca53

Height

#314,181

Difficulty

10.048548

Transactions

19

Size

6.25 KB

Version

2

Bits

0a0c6d9c

Nonce

183,102

Timestamp

12/15/2013, 8:18:19 PM

Confirmations

6,499,723

Merkle Root

4e209084fe058584d0af52acaec1aae0a792669b856a74993ccaebc3aa64631e
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.

3.453 × 10⁹³(94-digit number)
34535481731233590460…48564542784431833161
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
3.453 × 10⁹³(94-digit number)
34535481731233590460…48564542784431833161
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
6.907 × 10⁹³(94-digit number)
69070963462467180920…97129085568863666321
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
1.381 × 10⁹⁴(95-digit number)
13814192692493436184…94258171137727332641
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
2.762 × 10⁹⁴(95-digit number)
27628385384986872368…88516342275454665281
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
5.525 × 10⁹⁴(95-digit number)
55256770769973744736…77032684550909330561
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
1.105 × 10⁹⁵(96-digit number)
11051354153994748947…54065369101818661121
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
2.210 × 10⁹⁵(96-digit number)
22102708307989497894…08130738203637322241
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
4.420 × 10⁹⁵(96-digit number)
44205416615978995789…16261476407274644481
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
8.841 × 10⁹⁵(96-digit number)
88410833231957991578…32522952814549288961
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
1.768 × 10⁹⁶(97-digit number)
17682166646391598315…65045905629098577921
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 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
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 2CC formula:

2CC: p₁ (first prime), p₂ = 2p₁ − 1, p₃ = 2p₂ − 1, …
Circulating Supply:57,755,311 XPM·at block #6,813,903 · updates every 60s
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