Block #377,083

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 1/26/2014, 8:36:32 PM · Difficulty 10.4254 · 6,437,402 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
789600297792367ee70b401049b565805bef3ecddd0450407a945c1c623d7078

Height

#377,083

Difficulty

10.425367

Transactions

6

Size

1.74 KB

Version

2

Bits

0a6ce4d9

Nonce

94,885

Timestamp

1/26/2014, 8:36:32 PM

Confirmations

6,437,402

Merkle Root

263de57e9f7f6c116535ac49b71bcf0f1462b5475a6040c00ca2abfab18b6f94
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.

1.190 × 10⁹³(94-digit number)
11902487870724933814…85654373518602816001
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
1.190 × 10⁹³(94-digit number)
11902487870724933814…85654373518602816001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
2.380 × 10⁹³(94-digit number)
23804975741449867629…71308747037205632001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
4.760 × 10⁹³(94-digit number)
47609951482899735259…42617494074411264001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
9.521 × 10⁹³(94-digit number)
95219902965799470518…85234988148822528001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
1.904 × 10⁹⁴(95-digit number)
19043980593159894103…70469976297645056001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
3.808 × 10⁹⁴(95-digit number)
38087961186319788207…40939952595290112001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
7.617 × 10⁹⁴(95-digit number)
76175922372639576415…81879905190580224001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
1.523 × 10⁹⁵(96-digit number)
15235184474527915283…63759810381160448001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
3.047 × 10⁹⁵(96-digit number)
30470368949055830566…27519620762320896001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
6.094 × 10⁹⁵(96-digit number)
60940737898111661132…55039241524641792001
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:57,759,948 XPM·at block #6,814,484 · updates every 60s
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