Block #3,349,464

2CCLength 11★★★☆☆

Cunningham Chain of the Second Kind · Discovered 9/10/2019, 7:17:53 PM · Difficulty 11.0038 · 3,480,987 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
385ef76455bf431671f6b3bc9b9e5e59a8dc652d51301302db0cc1ca3d9aa4b1

Height

#3,349,464

Difficulty

11.003802

Transactions

4

Size

1.05 KB

Version

2

Bits

0b00f931

Nonce

1,917,540,525

Timestamp

9/10/2019, 7:17:53 PM

Confirmations

3,480,987

Merkle Root

18137d160bdcd2cf02ed47b3d56df65192f2d5c472e83234dcc3a3be2bf67142
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.

1.108 × 10⁹⁵(96-digit number)
11084151339766728646…11303373244153005441
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
1.108 × 10⁹⁵(96-digit number)
11084151339766728646…11303373244153005441
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
2.216 × 10⁹⁵(96-digit number)
22168302679533457292…22606746488306010881
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
4.433 × 10⁹⁵(96-digit number)
44336605359066914585…45213492976612021761
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
8.867 × 10⁹⁵(96-digit number)
88673210718133829170…90426985953224043521
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
1.773 × 10⁹⁶(97-digit number)
17734642143626765834…80853971906448087041
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
3.546 × 10⁹⁶(97-digit number)
35469284287253531668…61707943812896174081
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
7.093 × 10⁹⁶(97-digit number)
70938568574507063336…23415887625792348161
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
1.418 × 10⁹⁷(98-digit number)
14187713714901412667…46831775251584696321
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
2.837 × 10⁹⁷(98-digit number)
28375427429802825334…93663550503169392641
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
5.675 × 10⁹⁷(98-digit number)
56750854859605650669…87327101006338785281
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
11
2^10 × origin + 1
1.135 × 10⁹⁸(99-digit number)
11350170971921130133…74654202012677570561
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:57,887,853 XPM·at block #6,830,450 · updates every 60s
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