Block #314,752

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 12/16/2013, 3:39:13 AM · Difficulty 10.0727 · 6,482,150 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
248305a95da77f528f195109041ed43d4f55f4aca27686da9b5a89fdbf448614

Height

#314,752

Difficulty

10.072720

Transactions

33

Size

11.56 KB

Version

2

Bits

0a129dc8

Nonce

77,274

Timestamp

12/16/2013, 3:39:13 AM

Confirmations

6,482,150

Merkle Root

8bd12767ff676017961a5dba01a18dd25a13bd9edea5aae4af4c8946a6e41640
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.

6.145 × 10⁹⁴(95-digit number)
61459434475914809078…17668853227685549051
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
6.145 × 10⁹⁴(95-digit number)
61459434475914809078…17668853227685549051
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
1.229 × 10⁹⁵(96-digit number)
12291886895182961815…35337706455371098101
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
2.458 × 10⁹⁵(96-digit number)
24583773790365923631…70675412910742196201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
4.916 × 10⁹⁵(96-digit number)
49167547580731847262…41350825821484392401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
9.833 × 10⁹⁵(96-digit number)
98335095161463694525…82701651642968784801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
1.966 × 10⁹⁶(97-digit number)
19667019032292738905…65403303285937569601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
3.933 × 10⁹⁶(97-digit number)
39334038064585477810…30806606571875139201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
7.866 × 10⁹⁶(97-digit number)
78668076129170955620…61613213143750278401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
1.573 × 10⁹⁷(98-digit number)
15733615225834191124…23226426287500556801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
3.146 × 10⁹⁷(98-digit number)
31467230451668382248…46452852575001113601
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:57,619,237 XPM·at block #6,796,901 · updates every 60s
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