Block #785,043

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 10/27/2014, 7:29:10 AM · Difficulty 10.9752 · 6,020,873 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
3a764ea59275b0ca44bbd12541b539770ccd435449e5cd99ae06a34103359a9c

Height

#785,043

Difficulty

10.975155

Transactions

2

Size

2.74 KB

Version

2

Bits

0af9a3bc

Nonce

142,601,146

Timestamp

10/27/2014, 7:29:10 AM

Confirmations

6,020,873

Merkle Root

25c97a92cedb9960134e3a96403d7f0667d7cff35fa86cb0f751de902ea179e3
Transactions (2)
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.

1.632 × 10⁹⁸(99-digit number)
16323658673183182970…00663883456412467201
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
1.632 × 10⁹⁸(99-digit number)
16323658673183182970…00663883456412467201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
3.264 × 10⁹⁸(99-digit number)
32647317346366365941…01327766912824934401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
6.529 × 10⁹⁸(99-digit number)
65294634692732731883…02655533825649868801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
1.305 × 10⁹⁹(100-digit number)
13058926938546546376…05311067651299737601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
2.611 × 10⁹⁹(100-digit number)
26117853877093092753…10622135302599475201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
5.223 × 10⁹⁹(100-digit number)
52235707754186185506…21244270605198950401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
1.044 × 10¹⁰⁰(101-digit number)
10447141550837237101…42488541210397900801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
2.089 × 10¹⁰⁰(101-digit number)
20894283101674474202…84977082420795801601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
4.178 × 10¹⁰⁰(101-digit number)
41788566203348948405…69954164841591603201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
8.357 × 10¹⁰⁰(101-digit number)
83577132406697896810…39908329683183206401
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 Second 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 2CC formula:

2CC: p₁ (first prime), p₂ = 2p₁ − 1, p₃ = 2p₂ − 1, …
Circulating Supply:57,691,418 XPM·at block #6,805,915 · updates every 60s
xpmprime.info is a work in progress. If you enjoy using this service you can support this project with a Primecoin donation.