Block #1,334,664

2CCLength 11★★★☆☆

Cunningham Chain of the Second Kind · Discovered 11/20/2015, 12:03:02 PM · Difficulty 10.8327 · 5,479,804 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
a6bf9835ce0577d43cab3a8978f02e58701af9f8001256e01d77596b55ebbd9b

Height

#1,334,664

Difficulty

10.832697

Transactions

2

Size

1002 B

Version

2

Bits

0ad52ba5

Nonce

1,003,898,049

Timestamp

11/20/2015, 12:03:02 PM

Confirmations

5,479,804

Merkle Root

1b29c7931631a1cb537c3d4351845deb8f6d89fef8e30acff883055dde74557b
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.

8.333 × 10⁹³(94-digit number)
83335625984442334977…01571277481195998061
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
8.333 × 10⁹³(94-digit number)
83335625984442334977…01571277481195998061
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
1.666 × 10⁹⁴(95-digit number)
16667125196888466995…03142554962391996121
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
3.333 × 10⁹⁴(95-digit number)
33334250393776933990…06285109924783992241
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
6.666 × 10⁹⁴(95-digit number)
66668500787553867981…12570219849567984481
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
1.333 × 10⁹⁵(96-digit number)
13333700157510773596…25140439699135968961
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
2.666 × 10⁹⁵(96-digit number)
26667400315021547192…50280879398271937921
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
5.333 × 10⁹⁵(96-digit number)
53334800630043094385…00561758796543875841
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
1.066 × 10⁹⁶(97-digit number)
10666960126008618877…01123517593087751681
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
2.133 × 10⁹⁶(97-digit number)
21333920252017237754…02247035186175503361
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
4.266 × 10⁹⁶(97-digit number)
42667840504034475508…04494070372351006721
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
11
2^10 × origin + 1
8.533 × 10⁹⁶(97-digit number)
85335681008068951016…08988140744702013441
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:57,759,817 XPM·at block #6,814,467 · updates every 60s
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