Block #3,365,444

2CCLength 11★★★☆☆

Cunningham Chain of the Second Kind · Discovered 9/22/2019, 9:28:05 PM · Difficulty 10.9954 · 3,444,006 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
36bc538a4b17e10c95e6ed10a105fc636a4fcc97991421aae94d7c95406a6f5f

Height

#3,365,444

Difficulty

10.995376

Transactions

5

Size

1.76 KB

Version

2

Bits

0afed0f5

Nonce

1,299,554,022

Timestamp

9/22/2019, 9:28:05 PM

Confirmations

3,444,006

Merkle Root

55cf0c24a13ff3844752c833b1c71e8bd316d7b4030239307f5633992b799a1f
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.

2.626 × 10⁹⁴(95-digit number)
26262014354130352172…04981366035751450201
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
2.626 × 10⁹⁴(95-digit number)
26262014354130352172…04981366035751450201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
5.252 × 10⁹⁴(95-digit number)
52524028708260704344…09962732071502900401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
1.050 × 10⁹⁵(96-digit number)
10504805741652140868…19925464143005800801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
2.100 × 10⁹⁵(96-digit number)
21009611483304281737…39850928286011601601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
4.201 × 10⁹⁵(96-digit number)
42019222966608563475…79701856572023203201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
8.403 × 10⁹⁵(96-digit number)
84038445933217126950…59403713144046406401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
1.680 × 10⁹⁶(97-digit number)
16807689186643425390…18807426288092812801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
3.361 × 10⁹⁶(97-digit number)
33615378373286850780…37614852576185625601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
6.723 × 10⁹⁶(97-digit number)
67230756746573701560…75229705152371251201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
1.344 × 10⁹⁷(98-digit number)
13446151349314740312…50459410304742502401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
11
2^10 × origin + 1
2.689 × 10⁹⁷(98-digit number)
26892302698629480624…00918820609485004801
Verify on FactorDB ↗Wolfram Alpha ↗

What this block proved

The miner who found this block proved the existence of 11 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
RareChain length 11

Approximately 1 in 1,000 blocks. Noteworthy discoveries.

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:57,719,671 XPM·at block #6,809,449 · updates every 60s
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