Block #416,032

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 2/23/2014, 3:45:58 AM · Difficulty 10.3985 · 6,390,854 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
3ab7b64711608c4fc11d0f99a48c974a5cfdb7a495a607e3c4da367451325494

Height

#416,032

Difficulty

10.398451

Transactions

10

Size

2.60 KB

Version

2

Bits

0a6600e1

Nonce

84,389

Timestamp

2/23/2014, 3:45:58 AM

Confirmations

6,390,854

Merkle Root

8afedb6b319c05d56deec10632e3a7944c022a95874758cec91f9d7291b589c9
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.

7.557 × 10⁹⁰(91-digit number)
75572462776861880638…04842466922338907001
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
7.557 × 10⁹⁰(91-digit number)
75572462776861880638…04842466922338907001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
1.511 × 10⁹¹(92-digit number)
15114492555372376127…09684933844677814001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
3.022 × 10⁹¹(92-digit number)
30228985110744752255…19369867689355628001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
6.045 × 10⁹¹(92-digit number)
60457970221489504510…38739735378711256001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
1.209 × 10⁹²(93-digit number)
12091594044297900902…77479470757422512001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
2.418 × 10⁹²(93-digit number)
24183188088595801804…54958941514845024001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
4.836 × 10⁹²(93-digit number)
48366376177191603608…09917883029690048001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
9.673 × 10⁹²(93-digit number)
96732752354383207217…19835766059380096001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
1.934 × 10⁹³(94-digit number)
19346550470876641443…39671532118760192001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
3.869 × 10⁹³(94-digit number)
38693100941753282887…79343064237520384001
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:57,699,195 XPM·at block #6,806,885 · updates every 60s
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