Block #837,159

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 12/2/2014, 3:32:31 PM · Difficulty 10.9759 · 6,000,944 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
2b188a20095dd16857c2f98046fd7bd27e80631f4642c82d2ade368afe1163cb

Height

#837,159

Difficulty

10.975881

Transactions

7

Size

1.52 KB

Version

2

Bits

0af9d35b

Nonce

183,930,160

Timestamp

12/2/2014, 3:32:31 PM

Confirmations

6,000,944

Merkle Root

1f6226d41a7b1456dcd5d57e260f8e05fb5202cf4761841f134595e5df94ad3e
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.

2.236 × 10⁹⁴(95-digit number)
22367257352186794942…11886731983989296191
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
2.236 × 10⁹⁴(95-digit number)
22367257352186794942…11886731983989296191
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
4.473 × 10⁹⁴(95-digit number)
44734514704373589885…23773463967978592381
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
8.946 × 10⁹⁴(95-digit number)
89469029408747179770…47546927935957184761
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
1.789 × 10⁹⁵(96-digit number)
17893805881749435954…95093855871914369521
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
3.578 × 10⁹⁵(96-digit number)
35787611763498871908…90187711743828739041
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
7.157 × 10⁹⁵(96-digit number)
71575223526997743816…80375423487657478081
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
1.431 × 10⁹⁶(97-digit number)
14315044705399548763…60750846975314956161
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
2.863 × 10⁹⁶(97-digit number)
28630089410799097526…21501693950629912321
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
5.726 × 10⁹⁶(97-digit number)
57260178821598195052…43003387901259824641
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
1.145 × 10⁹⁷(98-digit number)
11452035764319639010…86006775802519649281
Verify on FactorDB ↗Wolfram Alpha ↗

What this block proved

The miner who found this block proved the existence of 10 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
UncommonChain length 10

Roughly 1 in 100 blocks. Solid but expected in a healthy network.

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:57,949,177 XPM·at block #6,838,102 · updates every 60s
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