Block #379,919

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 1/28/2014, 8:42:02 PM · Difficulty 10.4205 · 6,445,273 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
70a7c8dbda782ad07336dfa4f64095efbd9a54bc8e0d4552b91cdc66410a1ead

Height

#379,919

Difficulty

10.420483

Transactions

7

Size

1.64 KB

Version

2

Bits

0a6ba4c4

Nonce

96,174

Timestamp

1/28/2014, 8:42:02 PM

Confirmations

6,445,273

Merkle Root

5a321197ed1f16902f9a54bdd5e73331542241030ea5d10c915d68677f56ca3d
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.

1.430 × 10¹⁰⁴(105-digit number)
14305916718751244484…79877647067500708601
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
1.430 × 10¹⁰⁴(105-digit number)
14305916718751244484…79877647067500708601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
2.861 × 10¹⁰⁴(105-digit number)
28611833437502488969…59755294135001417201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
5.722 × 10¹⁰⁴(105-digit number)
57223666875004977938…19510588270002834401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
1.144 × 10¹⁰⁵(106-digit number)
11444733375000995587…39021176540005668801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
2.288 × 10¹⁰⁵(106-digit number)
22889466750001991175…78042353080011337601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
4.577 × 10¹⁰⁵(106-digit number)
45778933500003982350…56084706160022675201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
9.155 × 10¹⁰⁵(106-digit number)
91557867000007964701…12169412320045350401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
1.831 × 10¹⁰⁶(107-digit number)
18311573400001592940…24338824640090700801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
3.662 × 10¹⁰⁶(107-digit number)
36623146800003185880…48677649280181401601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
7.324 × 10¹⁰⁶(107-digit number)
73246293600006371761…97355298560362803201
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:57,845,627 XPM·at block #6,825,191 · updates every 60s
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