Block #1,432,076

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 1/28/2016, 3:31:01 AM · Difficulty 10.7818 · 5,394,867 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
8b7be29f3378b28f2c3df433976fab83fecca358b502d05c98a9e6f6d7c4345b

Height

#1,432,076

Difficulty

10.781790

Transactions

2

Size

3.74 KB

Version

2

Bits

0ac82369

Nonce

629,937,816

Timestamp

1/28/2016, 3:31:01 AM

Confirmations

5,394,867

Merkle Root

c58200d74bcf44f1b797d89800cee0a45e69568d78874e051b7d2c191b953d71
Transactions (2)
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.

2.961 × 10⁹⁶(97-digit number)
29619951064000007249…65772308492456903681
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
2.961 × 10⁹⁶(97-digit number)
29619951064000007249…65772308492456903681
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
5.923 × 10⁹⁶(97-digit number)
59239902128000014499…31544616984913807361
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
1.184 × 10⁹⁷(98-digit number)
11847980425600002899…63089233969827614721
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
2.369 × 10⁹⁷(98-digit number)
23695960851200005799…26178467939655229441
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
4.739 × 10⁹⁷(98-digit number)
47391921702400011599…52356935879310458881
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
9.478 × 10⁹⁷(98-digit number)
94783843404800023198…04713871758620917761
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
1.895 × 10⁹⁸(99-digit number)
18956768680960004639…09427743517241835521
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
3.791 × 10⁹⁸(99-digit number)
37913537361920009279…18855487034483671041
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
7.582 × 10⁹⁸(99-digit number)
75827074723840018558…37710974068967342081
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
1.516 × 10⁹⁹(100-digit number)
15165414944768003711…75421948137934684161
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:57,859,718 XPM·at block #6,826,942 · updates every 60s
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