Block #1,071,939

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 5/23/2015, 8:04:41 AM · Difficulty 10.7418 · 5,728,829 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
806f63c4981b7337f6984e4aafbab54cc0e1be2d704058ae3cea20da573c374b

Height

#1,071,939

Difficulty

10.741806

Transactions

19

Size

5.33 KB

Version

2

Bits

0abde705

Nonce

1,047,257,561

Timestamp

5/23/2015, 8:04:41 AM

Confirmations

5,728,829

Merkle Root

869d1335c0bd12e094e79ea09e0863344f6fd5dd44326851d4abf24b1e8699af
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.

9.237 × 10⁹⁵(96-digit number)
92373896726945334866…03027362183970880001
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
9.237 × 10⁹⁵(96-digit number)
92373896726945334866…03027362183970880001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
1.847 × 10⁹⁶(97-digit number)
18474779345389066973…06054724367941760001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
3.694 × 10⁹⁶(97-digit number)
36949558690778133946…12109448735883520001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
7.389 × 10⁹⁶(97-digit number)
73899117381556267893…24218897471767040001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
1.477 × 10⁹⁷(98-digit number)
14779823476311253578…48437794943534080001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
2.955 × 10⁹⁷(98-digit number)
29559646952622507157…96875589887068160001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
5.911 × 10⁹⁷(98-digit number)
59119293905245014314…93751179774136320001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
1.182 × 10⁹⁸(99-digit number)
11823858781049002862…87502359548272640001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
2.364 × 10⁹⁸(99-digit number)
23647717562098005725…75004719096545280001
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
4.729 × 10⁹⁸(99-digit number)
47295435124196011451…50009438193090560001
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:57,650,209 XPM·at block #6,800,767 · updates every 60s
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