Block #3,115,394

2CCLength 11★★★☆☆

Cunningham Chain of the Second Kind · Discovered 3/29/2019, 1:44:56 PM · Difficulty 11.2268 · 3,711,900 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
7b7e9de3bbaed94773812c841e7a1f2a8147eba0fe05dad30113f695bbe6498b

Height

#3,115,394

Difficulty

11.226819

Transactions

2

Size

576 B

Version

2

Bits

0b3a10d7

Nonce

225,901,616

Timestamp

3/29/2019, 1:44:56 PM

Confirmations

3,711,900

Merkle Root

3285bb1b2e325d8129dd478bb3f85164a68bb3fc4820280145001dd020c9f47b
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.

1.250 × 10⁹⁶(97-digit number)
12508245800523356750…16726471233200578561
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
1.250 × 10⁹⁶(97-digit number)
12508245800523356750…16726471233200578561
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
2.501 × 10⁹⁶(97-digit number)
25016491601046713500…33452942466401157121
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
5.003 × 10⁹⁶(97-digit number)
50032983202093427001…66905884932802314241
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
1.000 × 10⁹⁷(98-digit number)
10006596640418685400…33811769865604628481
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
2.001 × 10⁹⁷(98-digit number)
20013193280837370800…67623539731209256961
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
4.002 × 10⁹⁷(98-digit number)
40026386561674741601…35247079462418513921
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
8.005 × 10⁹⁷(98-digit number)
80052773123349483202…70494158924837027841
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
1.601 × 10⁹⁸(99-digit number)
16010554624669896640…40988317849674055681
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
3.202 × 10⁹⁸(99-digit number)
32021109249339793281…81976635699348111361
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
6.404 × 10⁹⁸(99-digit number)
64042218498679586562…63953271398696222721
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
11
2^10 × origin + 1
1.280 × 10⁹⁹(100-digit number)
12808443699735917312…27906542797392445441
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:57,862,461 XPM·at block #6,827,293 · updates every 60s
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