Block #328,036

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 12/24/2013, 11:45:50 PM · Difficulty 10.1731 · 6,463,987 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
50ad43872cfda1de79ddd91301aa17e50d2e6b510b251a67c11b6d6396382069

Height

#328,036

Difficulty

10.173103

Transactions

6

Size

1.90 KB

Version

2

Bits

0a2c5081

Nonce

15,495

Timestamp

12/24/2013, 11:45:50 PM

Confirmations

6,463,987

Merkle Root

78f6e752d1145cb2c0e8a1c15679664c5263be20dd3419a818377181ea3840b2
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.

6.025 × 10¹⁰⁰(101-digit number)
60252724561553557221…32802048465157231921
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
6.025 × 10¹⁰⁰(101-digit number)
60252724561553557221…32802048465157231921
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
1.205 × 10¹⁰¹(102-digit number)
12050544912310711444…65604096930314463841
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
2.410 × 10¹⁰¹(102-digit number)
24101089824621422888…31208193860628927681
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
4.820 × 10¹⁰¹(102-digit number)
48202179649242845777…62416387721257855361
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
9.640 × 10¹⁰¹(102-digit number)
96404359298485691554…24832775442515710721
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
1.928 × 10¹⁰²(103-digit number)
19280871859697138310…49665550885031421441
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
3.856 × 10¹⁰²(103-digit number)
38561743719394276621…99331101770062842881
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
7.712 × 10¹⁰²(103-digit number)
77123487438788553243…98662203540125685761
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
1.542 × 10¹⁰³(104-digit number)
15424697487757710648…97324407080251371521
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
3.084 × 10¹⁰³(104-digit number)
30849394975515421297…94648814160502743041
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:57,580,134 XPM·at block #6,792,022 · updates every 60s
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