Block #103,482

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 8/7/2013, 3:04:46 PM · Difficulty 9.5265 · 6,704,768 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
fddb9f6bad815388b22b4e23d9b243e9a8484ab86f07f89a137a1f3c4818890e

Height

#103,482

Difficulty

9.526503

Transactions

3

Size

652 B

Version

2

Bits

0986c8e7

Nonce

226,756

Timestamp

8/7/2013, 3:04:46 PM

Confirmations

6,704,768

Merkle Root

230417c9446e7d1eaf1705981af7f3f52cf3fa2e6c66fd5dbd377f49f1776af3
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.

9.995 × 10⁹⁹(100-digit number)
99950383022941779153…97633905250227089371
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
9.995 × 10⁹⁹(100-digit number)
99950383022941779153…97633905250227089371
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
1.999 × 10¹⁰⁰(101-digit number)
19990076604588355830…95267810500454178741
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
3.998 × 10¹⁰⁰(101-digit number)
39980153209176711661…90535621000908357481
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
7.996 × 10¹⁰⁰(101-digit number)
79960306418353423322…81071242001816714961
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
1.599 × 10¹⁰¹(102-digit number)
15992061283670684664…62142484003633429921
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
3.198 × 10¹⁰¹(102-digit number)
31984122567341369329…24284968007266859841
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
6.396 × 10¹⁰¹(102-digit number)
63968245134682738658…48569936014533719681
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
1.279 × 10¹⁰²(103-digit number)
12793649026936547731…97139872029067439361
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
2.558 × 10¹⁰²(103-digit number)
25587298053873095463…94279744058134878721
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
5.117 × 10¹⁰²(103-digit number)
51174596107746190926…88559488116269757441
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:57,710,045 XPM·at block #6,808,249 · updates every 60s
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