Block #2,376,827

1CCLength 11★★★☆☆

Cunningham Chain of the First Kind · Discovered 11/12/2017, 9:31:33 PM · Difficulty 10.8814 · 4,465,426 confirmations

1CC
Cunningham Chain of the First Kind

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

Block Header
Block Hash
7515b346f91796acda5f3c0404da6138eb40181cb1773ee17b92b83d7057eaf6

Height

#2,376,827

Difficulty

10.881383

Transactions

37

Size

8.90 KB

Version

2

Bits

0ae1a252

Nonce

839,419,757

Timestamp

11/12/2017, 9:31:33 PM

Confirmations

4,465,426

Merkle Root

5c2044eec5aceb5039279efa3d1a670ff1e0f2b77d979515c89e3391e55879f5
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.

2.935 × 10⁹⁴(95-digit number)
29357149904144562424…44821353861978860159
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
2.935 × 10⁹⁴(95-digit number)
29357149904144562424…44821353861978860159
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
2
2^1 × origin − 1
5.871 × 10⁹⁴(95-digit number)
58714299808289124849…89642707723957720319
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
3
2^2 × origin − 1
1.174 × 10⁹⁵(96-digit number)
11742859961657824969…79285415447915440639
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
4
2^3 × origin − 1
2.348 × 10⁹⁵(96-digit number)
23485719923315649939…58570830895830881279
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
5
2^4 × origin − 1
4.697 × 10⁹⁵(96-digit number)
46971439846631299879…17141661791661762559
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
6
2^5 × origin − 1
9.394 × 10⁹⁵(96-digit number)
93942879693262599759…34283323583323525119
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
7
2^6 × origin − 1
1.878 × 10⁹⁶(97-digit number)
18788575938652519951…68566647166647050239
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
8
2^7 × origin − 1
3.757 × 10⁹⁶(97-digit number)
37577151877305039903…37133294333294100479
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
9
2^8 × origin − 1
7.515 × 10⁹⁶(97-digit number)
75154303754610079807…74266588666588200959
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
10
2^9 × origin − 1
1.503 × 10⁹⁷(98-digit number)
15030860750922015961…48533177333176401919
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
11
2^10 × origin − 1
3.006 × 10⁹⁷(98-digit number)
30061721501844031923…97066354666352803839
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 First 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 1CC formula:

1CC: p₁ (first prime), p₂ = 2p₁ + 1, p₃ = 2p₂ + 1, …
Circulating Supply:57,982,421 XPM·at block #6,842,252 · updates every 60s
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