Block #723,795

1CCLength 11★★★☆☆

Cunningham Chain of the First Kind · Discovered 9/16/2014, 8:05:02 AM · Difficulty 10.9581 · 6,102,927 confirmations

1CC
Cunningham Chain of the First Kind

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

Block Header
Block Hash
a3d1b68e6b76968732018b6b37a96d9d09087048ca8f139fd519cc12f904f4ce

Height

#723,795

Difficulty

10.958120

Transactions

2

Size

465 B

Version

2

Bits

0af54758

Nonce

81,182,218

Timestamp

9/16/2014, 8:05:02 AM

Confirmations

6,102,927

Merkle Root

5443810eee6a42b2320fc4d3c303eba0ea6599f453ea7933f0743cc1d002ad15
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.

2.708 × 10⁹⁵(96-digit number)
27081919273699875180…56926470374707752399
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
2.708 × 10⁹⁵(96-digit number)
27081919273699875180…56926470374707752399
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
2
2^1 × origin − 1
5.416 × 10⁹⁵(96-digit number)
54163838547399750361…13852940749415504799
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
3
2^2 × origin − 1
1.083 × 10⁹⁶(97-digit number)
10832767709479950072…27705881498831009599
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
4
2^3 × origin − 1
2.166 × 10⁹⁶(97-digit number)
21665535418959900144…55411762997662019199
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
5
2^4 × origin − 1
4.333 × 10⁹⁶(97-digit number)
43331070837919800289…10823525995324038399
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
6
2^5 × origin − 1
8.666 × 10⁹⁶(97-digit number)
86662141675839600578…21647051990648076799
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
7
2^6 × origin − 1
1.733 × 10⁹⁷(98-digit number)
17332428335167920115…43294103981296153599
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
8
2^7 × origin − 1
3.466 × 10⁹⁷(98-digit number)
34664856670335840231…86588207962592307199
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
9
2^8 × origin − 1
6.932 × 10⁹⁷(98-digit number)
69329713340671680462…73176415925184614399
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
10
2^9 × origin − 1
1.386 × 10⁹⁸(99-digit number)
13865942668134336092…46352831850369228799
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
11
2^10 × origin − 1
2.773 × 10⁹⁸(99-digit number)
27731885336268672184…92705663700738457599
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:57,857,930 XPM·at block #6,826,721 · updates every 60s
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