Block #3,241,801

2CCLength 11★★★☆☆

Cunningham Chain of the Second Kind · Discovered 6/26/2019, 1:00:37 PM · Difficulty 11.0052 · 3,597,726 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
afb87df943b17ab3661e0d6e72510b8b338dd2207d1f8d7b28245e1e440cc891

Height

#3,241,801

Difficulty

11.005226

Transactions

4

Size

1.19 KB

Version

2

Bits

0b01567e

Nonce

1,707,371,831

Timestamp

6/26/2019, 1:00:37 PM

Confirmations

3,597,726

Merkle Root

3ed13145c5e7fe25c67994ad88aaceaacf76e909e625ae632128a4a4e68325ba
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.

2.701 × 10⁹⁶(97-digit number)
27011370664100204388…87551723158383641601
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
2.701 × 10⁹⁶(97-digit number)
27011370664100204388…87551723158383641601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
5.402 × 10⁹⁶(97-digit number)
54022741328200408777…75103446316767283201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
1.080 × 10⁹⁷(98-digit number)
10804548265640081755…50206892633534566401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
2.160 × 10⁹⁷(98-digit number)
21609096531280163511…00413785267069132801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
4.321 × 10⁹⁷(98-digit number)
43218193062560327022…00827570534138265601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
8.643 × 10⁹⁷(98-digit number)
86436386125120654044…01655141068276531201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
1.728 × 10⁹⁸(99-digit number)
17287277225024130808…03310282136553062401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
3.457 × 10⁹⁸(99-digit number)
34574554450048261617…06620564273106124801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
6.914 × 10⁹⁸(99-digit number)
69149108900096523235…13241128546212249601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
1.382 × 10⁹⁹(100-digit number)
13829821780019304647…26482257092424499201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
11
2^10 × origin + 1
2.765 × 10⁹⁹(100-digit number)
27659643560038609294…52964514184848998401
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:57,960,516 XPM·at block #6,839,526 · updates every 60s
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