Block #933,141

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 2/12/2015, 10:40:31 AM · Difficulty 10.9021 · 5,876,518 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
c3a9743f708539e7367b6dbf741c97f42736855658e45932c86d83055bc676c8

Height

#933,141

Difficulty

10.902078

Transactions

11

Size

4.72 KB

Version

2

Bits

0ae6ee9b

Nonce

249,091,826

Timestamp

2/12/2015, 10:40:31 AM

Confirmations

5,876,518

Merkle Root

0bfed26caa4e6ea16a3beb0082b452e43b7ee95064a01e50b93636617d2a2335
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.

1.271 × 10⁹⁵(96-digit number)
12718430366202450676…34843695248890975501
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
1.271 × 10⁹⁵(96-digit number)
12718430366202450676…34843695248890975501
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
2.543 × 10⁹⁵(96-digit number)
25436860732404901353…69687390497781951001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
5.087 × 10⁹⁵(96-digit number)
50873721464809802706…39374780995563902001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
1.017 × 10⁹⁶(97-digit number)
10174744292961960541…78749561991127804001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
2.034 × 10⁹⁶(97-digit number)
20349488585923921082…57499123982255608001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
4.069 × 10⁹⁶(97-digit number)
40698977171847842165…14998247964511216001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
8.139 × 10⁹⁶(97-digit number)
81397954343695684331…29996495929022432001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
1.627 × 10⁹⁷(98-digit number)
16279590868739136866…59992991858044864001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
3.255 × 10⁹⁷(98-digit number)
32559181737478273732…19985983716089728001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
6.511 × 10⁹⁷(98-digit number)
65118363474956547464…39971967432179456001
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:57,721,346 XPM·at block #6,809,658 · updates every 60s
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