Block #470,337

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 4/1/2014, 8:13:47 PM · Difficulty 10.4317 · 6,336,134 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
b39dd7fdfa3ca56135a97fc14d73a651fa8295c39b5671bb32738290d9c9c5c8

Height

#470,337

Difficulty

10.431730

Transactions

2

Size

80.92 KB

Version

2

Bits

0a6e85de

Nonce

195,790

Timestamp

4/1/2014, 8:13:47 PM

Confirmations

6,336,134

Merkle Root

f99bc337bcfa106124997ef325fc523c9f76edea445b62ce186246ccd81959f2
Transactions (2)
1 in → 1 out10.0100 XPM101 B
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.

1.249 × 10⁹⁷(98-digit number)
12498127895953801690…24379763705884760801
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
1.249 × 10⁹⁷(98-digit number)
12498127895953801690…24379763705884760801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
2.499 × 10⁹⁷(98-digit number)
24996255791907603381…48759527411769521601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
4.999 × 10⁹⁷(98-digit number)
49992511583815206762…97519054823539043201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
9.998 × 10⁹⁷(98-digit number)
99985023167630413524…95038109647078086401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
1.999 × 10⁹⁸(99-digit number)
19997004633526082704…90076219294156172801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
3.999 × 10⁹⁸(99-digit number)
39994009267052165409…80152438588312345601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
7.998 × 10⁹⁸(99-digit number)
79988018534104330819…60304877176624691201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
1.599 × 10⁹⁹(100-digit number)
15997603706820866163…20609754353249382401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
3.199 × 10⁹⁹(100-digit number)
31995207413641732327…41219508706498764801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
6.399 × 10⁹⁹(100-digit number)
63990414827283464655…82439017412997529601
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:57,695,862 XPM·at block #6,806,470 · updates every 60s
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