Block #3,048,874

2CCLength 11★★★☆☆

Cunningham Chain of the Second Kind · Discovered 2/11/2019, 9:23:19 PM · Difficulty 10.9961 · 3,792,835 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
ff0a353dd04f607cf3ba6161356bc758e0100429b7bacbad712ecf60c94891d0

Height

#3,048,874

Difficulty

10.996087

Transactions

2

Size

1.14 KB

Version

2

Bits

0afeff96

Nonce

358,999,951

Timestamp

2/11/2019, 9:23:19 PM

Confirmations

3,792,835

Merkle Root

1f609532a3887aeb5b1c5d119f71335b1c1143225d1f599264d19c7bb1e88288
Transactions (2)
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.

1.793 × 10⁹⁶(97-digit number)
17938935752980169410…21450291985455188801
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
1.793 × 10⁹⁶(97-digit number)
17938935752980169410…21450291985455188801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
3.587 × 10⁹⁶(97-digit number)
35877871505960338821…42900583970910377601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
7.175 × 10⁹⁶(97-digit number)
71755743011920677642…85801167941820755201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
1.435 × 10⁹⁷(98-digit number)
14351148602384135528…71602335883641510401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
2.870 × 10⁹⁷(98-digit number)
28702297204768271057…43204671767283020801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
5.740 × 10⁹⁷(98-digit number)
57404594409536542114…86409343534566041601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
1.148 × 10⁹⁸(99-digit number)
11480918881907308422…72818687069132083201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
2.296 × 10⁹⁸(99-digit number)
22961837763814616845…45637374138264166401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
4.592 × 10⁹⁸(99-digit number)
45923675527629233691…91274748276528332801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
9.184 × 10⁹⁸(99-digit number)
91847351055258467382…82549496553056665601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
11
2^10 × origin + 1
1.836 × 10⁹⁹(100-digit number)
18369470211051693476…65098993106113331201
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:57,978,051 XPM·at block #6,841,708 · updates every 60s
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