Block #922,294

2CCLength 11★★★☆☆

Cunningham Chain of the Second Kind · Discovered 2/4/2015, 8:55:33 AM · Difficulty 10.9157 · 5,888,161 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
65403b1ccb3dc8fa33f3af5ba179c313675bc77e7c0f55ab6322609c6ad87620

Height

#922,294

Difficulty

10.915739

Transactions

12

Size

318.58 KB

Version

2

Bits

0aea6ddc

Nonce

300,619,852

Timestamp

2/4/2015, 8:55:33 AM

Confirmations

5,888,161

Merkle Root

4e0c79100eb6352611116d68b6fcc7a7f907e6dcbef70df803819cdcd57493b8
Transactions (12)
1 in → 1 out11.6800 XPM109 B
200 in → 1 out1150.2410 XPM28.96 KB
200 in → 1 out1022.0886 XPM28.94 KB
200 in → 1 out1080.6975 XPM28.94 KB
200 in → 1 out901.5651 XPM28.94 KB
200 in → 1 out1032.6986 XPM28.94 KB
200 in → 1 out951.4165 XPM28.94 KB
200 in → 1 out1067.5518 XPM28.95 KB
200 in → 1 out1073.5490 XPM28.95 KB
200 in → 1 out995.9255 XPM28.95 KB
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.

3.024 × 10⁹⁵(96-digit number)
30242216543580285146…53253244459780321281
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
3.024 × 10⁹⁵(96-digit number)
30242216543580285146…53253244459780321281
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
6.048 × 10⁹⁵(96-digit number)
60484433087160570293…06506488919560642561
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
1.209 × 10⁹⁶(97-digit number)
12096886617432114058…13012977839121285121
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
2.419 × 10⁹⁶(97-digit number)
24193773234864228117…26025955678242570241
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
4.838 × 10⁹⁶(97-digit number)
48387546469728456234…52051911356485140481
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
9.677 × 10⁹⁶(97-digit number)
96775092939456912468…04103822712970280961
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
1.935 × 10⁹⁷(98-digit number)
19355018587891382493…08207645425940561921
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
3.871 × 10⁹⁷(98-digit number)
38710037175782764987…16415290851881123841
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
7.742 × 10⁹⁷(98-digit number)
77420074351565529975…32830581703762247681
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
1.548 × 10⁹⁸(99-digit number)
15484014870313105995…65661163407524495361
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
11
2^10 × origin + 1
3.096 × 10⁹⁸(99-digit number)
30968029740626211990…31322326815048990721
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:57,727,726 XPM·at block #6,810,454 · updates every 60s
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