Block #370,275

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 1/22/2014, 12:17:59 AM · Difficulty 10.4430 · 6,430,991 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
9b3bbb1d59473c541826c3302218ef2bb9f4d6e6555897483e6c67338d26de79

Height

#370,275

Difficulty

10.442983

Transactions

6

Size

2.56 KB

Version

2

Bits

0a716758

Nonce

353,200

Timestamp

1/22/2014, 12:17:59 AM

Confirmations

6,430,991

Merkle Root

23f12d97bb22ce4f6d499f4ca87bdf2b5dc05e2d7768471cd307bdb2ec4e8040
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.

3.312 × 10¹⁰⁰(101-digit number)
33126048862199911696…10957184252872469761
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
3.312 × 10¹⁰⁰(101-digit number)
33126048862199911696…10957184252872469761
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
6.625 × 10¹⁰⁰(101-digit number)
66252097724399823393…21914368505744939521
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
1.325 × 10¹⁰¹(102-digit number)
13250419544879964678…43828737011489879041
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
2.650 × 10¹⁰¹(102-digit number)
26500839089759929357…87657474022979758081
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
5.300 × 10¹⁰¹(102-digit number)
53001678179519858714…75314948045959516161
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
1.060 × 10¹⁰²(103-digit number)
10600335635903971742…50629896091919032321
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
2.120 × 10¹⁰²(103-digit number)
21200671271807943485…01259792183838064641
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
4.240 × 10¹⁰²(103-digit number)
42401342543615886971…02519584367676129281
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
8.480 × 10¹⁰²(103-digit number)
84802685087231773943…05039168735352258561
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
1.696 × 10¹⁰³(104-digit number)
16960537017446354788…10078337470704517121
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:57,654,199 XPM·at block #6,801,265 · updates every 60s
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