Block #1,000,283

2CCLength 11★★★☆☆

Cunningham Chain of the Second Kind · Discovered 4/3/2015, 12:21:53 AM · Difficulty 10.7777 · 5,809,787 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
b66cee2ff5d6fd6d7faaa3a053819da63ce39e32389bab46e4de5dd32e24ae4c

Height

#1,000,283

Difficulty

10.777712

Transactions

6

Size

6.19 KB

Version

2

Bits

0ac7181a

Nonce

153,109,589

Timestamp

4/3/2015, 12:21:53 AM

Confirmations

5,809,787

Merkle Root

0ca62a7ee722b70e237c763c27b09713fbeb151ce2156959d0e89ecb251ab2ed
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.

4.571 × 10⁹⁶(97-digit number)
45714161664173266814…56423370828315815361
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
4.571 × 10⁹⁶(97-digit number)
45714161664173266814…56423370828315815361
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
9.142 × 10⁹⁶(97-digit number)
91428323328346533628…12846741656631630721
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
1.828 × 10⁹⁷(98-digit number)
18285664665669306725…25693483313263261441
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
3.657 × 10⁹⁷(98-digit number)
36571329331338613451…51386966626526522881
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
7.314 × 10⁹⁷(98-digit number)
73142658662677226903…02773933253053045761
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
1.462 × 10⁹⁸(99-digit number)
14628531732535445380…05547866506106091521
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
2.925 × 10⁹⁸(99-digit number)
29257063465070890761…11095733012212183041
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
5.851 × 10⁹⁸(99-digit number)
58514126930141781522…22191466024424366081
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
1.170 × 10⁹⁹(100-digit number)
11702825386028356304…44382932048848732161
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
2.340 × 10⁹⁹(100-digit number)
23405650772056712608…88765864097697464321
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
11
2^10 × origin + 1
4.681 × 10⁹⁹(100-digit number)
46811301544113425217…77531728195394928641
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 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
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 2CC formula:

2CC: p₁ (first prime), p₂ = 2p₁ − 1, p₃ = 2p₂ − 1, …
Circulating Supply:57,724,632 XPM·at block #6,810,069 · updates every 60s
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