Block #244,805

1CCLength 11★★★☆☆

Cunningham Chain of the First Kind · Discovered 11/5/2013, 2:31:08 AM · Difficulty 9.9632 · 6,588,221 confirmations

1CC
Cunningham Chain of the First Kind

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

Block Header
Block Hash
ec8d071808a65fe4107d6b3f6e9ea036593d63660f102458348e7ecb4f9efb2c

Height

#244,805

Difficulty

9.963162

Transactions

1

Size

1.91 KB

Version

2

Bits

09f691cf

Nonce

14,676

Timestamp

11/5/2013, 2:31:08 AM

Confirmations

6,588,221

Merkle Root

1965dfa994e5ff21aea2caa20fd3a2efb7e7e7ef56aad05d76242f187e7760ca
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.

6.269 × 10⁸⁸(89-digit number)
62691769333013347171…86217653965293102559
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
6.269 × 10⁸⁸(89-digit number)
62691769333013347171…86217653965293102559
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
2
2^1 × origin − 1
1.253 × 10⁸⁹(90-digit number)
12538353866602669434…72435307930586205119
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
3
2^2 × origin − 1
2.507 × 10⁸⁹(90-digit number)
25076707733205338868…44870615861172410239
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
4
2^3 × origin − 1
5.015 × 10⁸⁹(90-digit number)
50153415466410677737…89741231722344820479
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
5
2^4 × origin − 1
1.003 × 10⁹⁰(91-digit number)
10030683093282135547…79482463444689640959
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
6
2^5 × origin − 1
2.006 × 10⁹⁰(91-digit number)
20061366186564271094…58964926889379281919
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
7
2^6 × origin − 1
4.012 × 10⁹⁰(91-digit number)
40122732373128542189…17929853778758563839
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
8
2^7 × origin − 1
8.024 × 10⁹⁰(91-digit number)
80245464746257084379…35859707557517127679
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
9
2^8 × origin − 1
1.604 × 10⁹¹(92-digit number)
16049092949251416875…71719415115034255359
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
10
2^9 × origin − 1
3.209 × 10⁹¹(92-digit number)
32098185898502833751…43438830230068510719
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
11
2^10 × origin − 1
6.419 × 10⁹¹(92-digit number)
64196371797005667503…86877660460137021439
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:57,908,384 XPM·at block #6,833,025 · updates every 60s
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