Block #3,011,138

2CCLength 11★★★☆☆

Cunningham Chain of the Second Kind · Discovered 1/15/2019, 7:43:59 PM · Difficulty 11.2008 · 3,829,984 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
f4a54b91636076c3697cd30c7b8b13cecb52018dd2be2eb149d72f7b5e3eee87

Height

#3,011,138

Difficulty

11.200844

Transactions

4

Size

1.05 KB

Version

2

Bits

0b336a86

Nonce

2,084,808,911

Timestamp

1/15/2019, 7:43:59 PM

Confirmations

3,829,984

Merkle Root

30f42778b131212de0ca18a67b400d74a27a430a26f6315cea3667926a68c274
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.

1.691 × 10⁹⁸(99-digit number)
16918637325544112028…83519735985020600321
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
1.691 × 10⁹⁸(99-digit number)
16918637325544112028…83519735985020600321
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
3.383 × 10⁹⁸(99-digit number)
33837274651088224056…67039471970041200641
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
6.767 × 10⁹⁸(99-digit number)
67674549302176448112…34078943940082401281
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
1.353 × 10⁹⁹(100-digit number)
13534909860435289622…68157887880164802561
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
2.706 × 10⁹⁹(100-digit number)
27069819720870579244…36315775760329605121
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
5.413 × 10⁹⁹(100-digit number)
54139639441741158489…72631551520659210241
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
1.082 × 10¹⁰⁰(101-digit number)
10827927888348231697…45263103041318420481
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
2.165 × 10¹⁰⁰(101-digit number)
21655855776696463395…90526206082636840961
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
4.331 × 10¹⁰⁰(101-digit number)
43311711553392926791…81052412165273681921
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
8.662 × 10¹⁰⁰(101-digit number)
86623423106785853583…62104824330547363841
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
11
2^10 × origin + 1
1.732 × 10¹⁰¹(102-digit number)
17324684621357170716…24209648661094727681
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:57,973,345 XPM·at block #6,841,121 · updates every 60s
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