Block #314,219

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 12/15/2013, 8:47:39 PM · Difficulty 10.0499 · 6,491,686 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
f8a9f3425f89b644a8fd41c8aaf56f51c7ecb757caebddda5db11e1cab0056bb

Height

#314,219

Difficulty

10.049931

Transactions

17

Size

4.48 KB

Version

2

Bits

0a0cc845

Nonce

312,671

Timestamp

12/15/2013, 8:47:39 PM

Confirmations

6,491,686

Merkle Root

c99271db472a9598e390509dcb8931b3e9d1d8c95bab9bac719c694c9c1c60dd
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.

7.228 × 10⁹⁴(95-digit number)
72283602775453137625…07838683988180378111
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
7.228 × 10⁹⁴(95-digit number)
72283602775453137625…07838683988180378111
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
1.445 × 10⁹⁵(96-digit number)
14456720555090627525…15677367976360756221
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
2.891 × 10⁹⁵(96-digit number)
28913441110181255050…31354735952721512441
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
5.782 × 10⁹⁵(96-digit number)
57826882220362510100…62709471905443024881
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
1.156 × 10⁹⁶(97-digit number)
11565376444072502020…25418943810886049761
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
2.313 × 10⁹⁶(97-digit number)
23130752888145004040…50837887621772099521
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
4.626 × 10⁹⁶(97-digit number)
46261505776290008080…01675775243544199041
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
9.252 × 10⁹⁶(97-digit number)
92523011552580016160…03351550487088398081
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
1.850 × 10⁹⁷(98-digit number)
18504602310516003232…06703100974176796161
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
3.700 × 10⁹⁷(98-digit number)
37009204621032006464…13406201948353592321
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:57,691,329 XPM·at block #6,805,904 · updates every 60s
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