Block #282,887

1CCLength 11★★★☆☆

Cunningham Chain of the First Kind · Discovered 11/29/2013, 1:14:43 PM · Difficulty 9.9800 · 6,535,077 confirmations

1CC
Cunningham Chain of the First Kind

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

Block Header
Block Hash
6275d405178bca94dcef86c839bb84ce8f220cf0fb71501cdda331289bb56d31

Height

#282,887

Difficulty

9.980043

Transactions

3

Size

684 B

Version

2

Bits

09fae41d

Nonce

4,194

Timestamp

11/29/2013, 1:14:43 PM

Confirmations

6,535,077

Merkle Root

93441a8aa73240664bc2ce84fb91d535abb86a639f1a99c9734315ac314fb9d7
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.

2.109 × 10⁹⁹(100-digit number)
21097552164714641329…45153294386577828089
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
2.109 × 10⁹⁹(100-digit number)
21097552164714641329…45153294386577828089
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
2
2^1 × origin − 1
4.219 × 10⁹⁹(100-digit number)
42195104329429282659…90306588773155656179
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
3
2^2 × origin − 1
8.439 × 10⁹⁹(100-digit number)
84390208658858565319…80613177546311312359
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
4
2^3 × origin − 1
1.687 × 10¹⁰⁰(101-digit number)
16878041731771713063…61226355092622624719
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
5
2^4 × origin − 1
3.375 × 10¹⁰⁰(101-digit number)
33756083463543426127…22452710185245249439
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
6
2^5 × origin − 1
6.751 × 10¹⁰⁰(101-digit number)
67512166927086852255…44905420370490498879
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
7
2^6 × origin − 1
1.350 × 10¹⁰¹(102-digit number)
13502433385417370451…89810840740980997759
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
8
2^7 × origin − 1
2.700 × 10¹⁰¹(102-digit number)
27004866770834740902…79621681481961995519
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
9
2^8 × origin − 1
5.400 × 10¹⁰¹(102-digit number)
54009733541669481804…59243362963923991039
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
10
2^9 × origin − 1
1.080 × 10¹⁰²(103-digit number)
10801946708333896360…18486725927847982079
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
11
2^10 × origin − 1
2.160 × 10¹⁰²(103-digit number)
21603893416667792721…36973451855695964159
Verify on FactorDB ↗Wolfram Alpha ↗

What this block proved

The miner who found this block proved the existence of 11 consecutive prime numbers forming a Cunningham Chain of the First 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
RareChain length 11

Approximately 1 in 1,000 blocks. Noteworthy discoveries.

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 1CC formula:

1CC: p₁ (first prime), p₂ = 2p₁ + 1, p₃ = 2p₂ + 1, …
Circulating Supply:57,787,781 XPM·at block #6,817,963 · updates every 60s
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