Block #64,832

1CCLength 9★☆☆☆☆

Cunningham Chain of the First Kind · Discovered 7/19/2013, 9:21:50 AM · Difficulty 8.9827 · 6,760,581 confirmations

1CC
Cunningham Chain of the First Kind

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

Block Header
Block Hash
922b3e9d4ed69af5360607c615707d7dc84f4b61962f90d5544d8b68519b88b7

Height

#64,832

Difficulty

8.982688

Transactions

3

Size

2.27 KB

Version

2

Bits

08fb916c

Nonce

1,020

Timestamp

7/19/2013, 9:21:50 AM

Confirmations

6,760,581

Merkle Root

d4fd76728982ec53f0a4b0acd80e7f1f9803a677066705724f73c9153c681ed5
Transactions (3)
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.

5.138 × 10⁹³(94-digit number)
51383672615225569691…86984521190498708679
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
5.138 × 10⁹³(94-digit number)
51383672615225569691…86984521190498708679
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
2
2^1 × origin − 1
1.027 × 10⁹⁴(95-digit number)
10276734523045113938…73969042380997417359
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
3
2^2 × origin − 1
2.055 × 10⁹⁴(95-digit number)
20553469046090227876…47938084761994834719
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
4
2^3 × origin − 1
4.110 × 10⁹⁴(95-digit number)
41106938092180455753…95876169523989669439
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
5
2^4 × origin − 1
8.221 × 10⁹⁴(95-digit number)
82213876184360911506…91752339047979338879
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
6
2^5 × origin − 1
1.644 × 10⁹⁵(96-digit number)
16442775236872182301…83504678095958677759
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
7
2^6 × origin − 1
3.288 × 10⁹⁵(96-digit number)
32885550473744364602…67009356191917355519
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
8
2^7 × origin − 1
6.577 × 10⁹⁵(96-digit number)
65771100947488729205…34018712383834711039
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
9
2^8 × origin − 1
1.315 × 10⁹⁶(97-digit number)
13154220189497745841…68037424767669422079
Verify on FactorDB ↗Wolfram Alpha ↗

What this block proved

The miner who found this block proved the existence of 9 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
CommonChain length 9

Found in most blocks. The baseline for Primecoin's proof-of-work.

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:57,847,404 XPM·at block #6,825,412 · updates every 60s
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