Block #1,429,570

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 1/27/2016, 12:03:25 AM · Difficulty 10.7412 · 5,397,429 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
b9ef35995aa9d46631a8fd0520c7ca6af3a214e28a91f597760b74a7c4a80b8e

Height

#1,429,570

Difficulty

10.741175

Transactions

2

Size

767 B

Version

2

Bits

0abdbda2

Nonce

31,674,752

Timestamp

1/27/2016, 12:03:25 AM

Confirmations

5,397,429

Merkle Root

7372cf6254fe15acf03233f7cb2d433127dd6902ef303df172cf8a5e00c64602
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.

1.891 × 10⁹⁶(97-digit number)
18916762355818136513…38758185759997432321
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
1.891 × 10⁹⁶(97-digit number)
18916762355818136513…38758185759997432321
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
3.783 × 10⁹⁶(97-digit number)
37833524711636273027…77516371519994864641
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
7.566 × 10⁹⁶(97-digit number)
75667049423272546055…55032743039989729281
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
1.513 × 10⁹⁷(98-digit number)
15133409884654509211…10065486079979458561
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
3.026 × 10⁹⁷(98-digit number)
30266819769309018422…20130972159958917121
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
6.053 × 10⁹⁷(98-digit number)
60533639538618036844…40261944319917834241
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
1.210 × 10⁹⁸(99-digit number)
12106727907723607368…80523888639835668481
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
2.421 × 10⁹⁸(99-digit number)
24213455815447214737…61047777279671336961
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
4.842 × 10⁹⁸(99-digit number)
48426911630894429475…22095554559342673921
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
9.685 × 10⁹⁸(99-digit number)
96853823261788858950…44191109118685347841
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:57,860,168 XPM·at block #6,826,998 · updates every 60s
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