Block #2,939,782

1CCLength 11★★★☆☆

Cunningham Chain of the First Kind · Discovered 11/26/2018, 9:42:40 AM · Difficulty 11.3731 · 3,896,903 confirmations

1CC
Cunningham Chain of the First Kind

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

Block Header
Block Hash
045bd1652c61f56f3bc83b9b0bfe707d85f21c4827eb03d3ffadeb18e1ceae33

Height

#2,939,782

Difficulty

11.373093

Transactions

2

Size

2.61 KB

Version

2

Bits

0b5f82fe

Nonce

790,255,168

Timestamp

11/26/2018, 9:42:40 AM

Confirmations

3,896,903

Merkle Root

3b2ed62888a15cf2d78b14e8825ae242c80707c7bfbe784c505da55b736fa43b
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.

1.190 × 10⁹⁴(95-digit number)
11902747804244477826…34467459882729582079
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
1.190 × 10⁹⁴(95-digit number)
11902747804244477826…34467459882729582079
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
2
2^1 × origin − 1
2.380 × 10⁹⁴(95-digit number)
23805495608488955652…68934919765459164159
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
3
2^2 × origin − 1
4.761 × 10⁹⁴(95-digit number)
47610991216977911305…37869839530918328319
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
4
2^3 × origin − 1
9.522 × 10⁹⁴(95-digit number)
95221982433955822611…75739679061836656639
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
5
2^4 × origin − 1
1.904 × 10⁹⁵(96-digit number)
19044396486791164522…51479358123673313279
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
6
2^5 × origin − 1
3.808 × 10⁹⁵(96-digit number)
38088792973582329044…02958716247346626559
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
7
2^6 × origin − 1
7.617 × 10⁹⁵(96-digit number)
76177585947164658088…05917432494693253119
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
8
2^7 × origin − 1
1.523 × 10⁹⁶(97-digit number)
15235517189432931617…11834864989386506239
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
9
2^8 × origin − 1
3.047 × 10⁹⁶(97-digit number)
30471034378865863235…23669729978773012479
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
10
2^9 × origin − 1
6.094 × 10⁹⁶(97-digit number)
60942068757731726471…47339459957546024959
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
11
2^10 × origin − 1
1.218 × 10⁹⁷(98-digit number)
12188413751546345294…94678919915092049919
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:57,937,761 XPM·at block #6,836,684 · updates every 60s
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