Block #499,726

1CCLength 10★★☆☆☆

Cunningham Chain of the First Kind · Discovered 4/18/2014, 6:15:29 PM · Difficulty 10.7947 · 6,316,990 confirmations

1CC
Cunningham Chain of the First Kind

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

Block Header
Block Hash
c6dc856262e7c5f9bf131f2ab34033c1b68d65233ec5c4a9917b5ab7481cc65b

Height

#499,726

Difficulty

10.794671

Transactions

1

Size

834 B

Version

2

Bits

0acb6f87

Nonce

176,620

Timestamp

4/18/2014, 6:15:29 PM

Confirmations

6,316,990

Merkle Root

6ed5d3aad4b68769adb53f907bcf7ea9f702ffc1b25a057b69b1327637017e7c
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.

2.155 × 10⁹⁶(97-digit number)
21557741373479616374…98662545325361683519
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
2.155 × 10⁹⁶(97-digit number)
21557741373479616374…98662545325361683519
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
2
2^1 × origin − 1
4.311 × 10⁹⁶(97-digit number)
43115482746959232748…97325090650723367039
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
3
2^2 × origin − 1
8.623 × 10⁹⁶(97-digit number)
86230965493918465496…94650181301446734079
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
4
2^3 × origin − 1
1.724 × 10⁹⁷(98-digit number)
17246193098783693099…89300362602893468159
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
5
2^4 × origin − 1
3.449 × 10⁹⁷(98-digit number)
34492386197567386198…78600725205786936319
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
6
2^5 × origin − 1
6.898 × 10⁹⁷(98-digit number)
68984772395134772397…57201450411573872639
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
7
2^6 × origin − 1
1.379 × 10⁹⁸(99-digit number)
13796954479026954479…14402900823147745279
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
8
2^7 × origin − 1
2.759 × 10⁹⁸(99-digit number)
27593908958053908958…28805801646295490559
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
9
2^8 × origin − 1
5.518 × 10⁹⁸(99-digit number)
55187817916107817917…57611603292590981119
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
10
2^9 × origin − 1
1.103 × 10⁹⁹(100-digit number)
11037563583221563583…15223206585181962239
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 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
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 1CC formula:

1CC: p₁ (first prime), p₂ = 2p₁ + 1, p₃ = 2p₂ + 1, …
Circulating Supply:57,777,852 XPM·at block #6,816,715 · updates every 60s
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