Block #1,046,838

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 5/6/2015, 1:34:27 AM · Difficulty 10.7287 · 5,763,075 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
4b9406f5203a0e7d7f8d0b29ddbf7ea51989300033102e2a31047326dd07164a

Height

#1,046,838

Difficulty

10.728704

Transactions

3

Size

800 B

Version

2

Bits

0aba8c5d

Nonce

505,527,246

Timestamp

5/6/2015, 1:34:27 AM

Confirmations

5,763,075

Merkle Root

f182044b31dac8f59beff6e1055d3b849de4d3567382a321489348a19ddc89b7
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.

2.544 × 10⁹⁵(96-digit number)
25447598734555037909…99703915918532162561
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
2.544 × 10⁹⁵(96-digit number)
25447598734555037909…99703915918532162561
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
5.089 × 10⁹⁵(96-digit number)
50895197469110075818…99407831837064325121
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
1.017 × 10⁹⁶(97-digit number)
10179039493822015163…98815663674128650241
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
2.035 × 10⁹⁶(97-digit number)
20358078987644030327…97631327348257300481
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
4.071 × 10⁹⁶(97-digit number)
40716157975288060655…95262654696514600961
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
8.143 × 10⁹⁶(97-digit number)
81432315950576121310…90525309393029201921
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
1.628 × 10⁹⁷(98-digit number)
16286463190115224262…81050618786058403841
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
3.257 × 10⁹⁷(98-digit number)
32572926380230448524…62101237572116807681
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
6.514 × 10⁹⁷(98-digit number)
65145852760460897048…24202475144233615361
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
1.302 × 10⁹⁸(99-digit number)
13029170552092179409…48404950288467230721
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:57,723,388 XPM·at block #6,809,912 · updates every 60s
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