Block #2,654,744

1CCLength 11★★★☆☆

Cunningham Chain of the First Kind · Discovered 5/9/2018, 2:32:51 PM · Difficulty 11.7149 · 4,175,992 confirmations

1CC
Cunningham Chain of the First Kind

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

Block Header
Block Hash
8631f12aed5175b4858b0f4098e12766639ecf6bf45af9bffc0a2f3c3f8c5e1c

Height

#2,654,744

Difficulty

11.714894

Transactions

3

Size

949 B

Version

2

Bits

0bb70351

Nonce

377,949,067

Timestamp

5/9/2018, 2:32:51 PM

Confirmations

4,175,992

Merkle Root

2ecde51dca89a61ef182c82eb9e0adbf98fe45790b194d2c3b28224ba2ad4787
Transactions (3)
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.

3.999 × 10⁹³(94-digit number)
39993877968407061510…35307353172811509299
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
3.999 × 10⁹³(94-digit number)
39993877968407061510…35307353172811509299
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
2
2^1 × origin − 1
7.998 × 10⁹³(94-digit number)
79987755936814123020…70614706345623018599
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
3
2^2 × origin − 1
1.599 × 10⁹⁴(95-digit number)
15997551187362824604…41229412691246037199
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
4
2^3 × origin − 1
3.199 × 10⁹⁴(95-digit number)
31995102374725649208…82458825382492074399
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
5
2^4 × origin − 1
6.399 × 10⁹⁴(95-digit number)
63990204749451298416…64917650764984148799
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
6
2^5 × origin − 1
1.279 × 10⁹⁵(96-digit number)
12798040949890259683…29835301529968297599
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
7
2^6 × origin − 1
2.559 × 10⁹⁵(96-digit number)
25596081899780519366…59670603059936595199
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
8
2^7 × origin − 1
5.119 × 10⁹⁵(96-digit number)
51192163799561038733…19341206119873190399
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
9
2^8 × origin − 1
1.023 × 10⁹⁶(97-digit number)
10238432759912207746…38682412239746380799
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
10
2^9 × origin − 1
2.047 × 10⁹⁶(97-digit number)
20476865519824415493…77364824479492761599
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
11
2^10 × origin − 1
4.095 × 10⁹⁶(97-digit number)
40953731039648830986…54729648958985523199
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:57,890,025 XPM·at block #6,830,735 · updates every 60s
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