Block #3,232,778

2CCLength 11★★★☆☆

Cunningham Chain of the Second Kind · Discovered 6/20/2019, 2:13:50 AM · Difficulty 11.0001 · 3,603,943 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
5ff158f364e77288a71182332998a8b1387c8d05cfc7d27fe90c8a100d0e97df

Height

#3,232,778

Difficulty

11.000099

Transactions

5

Size

2.86 KB

Version

2

Bits

0b000683

Nonce

755,242,385

Timestamp

6/20/2019, 2:13:50 AM

Confirmations

3,603,943

Merkle Root

b3a40bba8e6fdfb0bc6a48b24bb504b8c72daac7243fead8d9207815387760ef
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.

2.750 × 10⁹⁴(95-digit number)
27505607316377145265…29816384163853929521
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
2.750 × 10⁹⁴(95-digit number)
27505607316377145265…29816384163853929521
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
5.501 × 10⁹⁴(95-digit number)
55011214632754290531…59632768327707859041
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
1.100 × 10⁹⁵(96-digit number)
11002242926550858106…19265536655415718081
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
2.200 × 10⁹⁵(96-digit number)
22004485853101716212…38531073310831436161
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
4.400 × 10⁹⁵(96-digit number)
44008971706203432425…77062146621662872321
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
8.801 × 10⁹⁵(96-digit number)
88017943412406864851…54124293243325744641
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
1.760 × 10⁹⁶(97-digit number)
17603588682481372970…08248586486651489281
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
3.520 × 10⁹⁶(97-digit number)
35207177364962745940…16497172973302978561
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
7.041 × 10⁹⁶(97-digit number)
70414354729925491880…32994345946605957121
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
1.408 × 10⁹⁷(98-digit number)
14082870945985098376…65988691893211914241
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
11
2^10 × origin + 1
2.816 × 10⁹⁷(98-digit number)
28165741891970196752…31977383786423828481
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:57,938,050 XPM·at block #6,836,720 · updates every 60s
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