Block #910,637

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 1/26/2015, 11:03:21 AM · Difficulty 10.9329 · 5,900,420 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
a229297e99810b6b329cfbaaddab32fcd870bd8e7682712c6b6e90cc78c486eb

Height

#910,637

Difficulty

10.932916

Transactions

10

Size

20.11 KB

Version

2

Bits

0aeed39d

Nonce

3,135,965,010

Timestamp

1/26/2015, 11:03:21 AM

Confirmations

5,900,420

Merkle Root

fda77478d23ffdc498b7e17e6b5d6ad322d4dae17f1ee1851ca50f1ffee3b938
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.

1.061 × 10⁹⁵(96-digit number)
10614993887047078788…81462579011340126061
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
1.061 × 10⁹⁵(96-digit number)
10614993887047078788…81462579011340126061
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
2.122 × 10⁹⁵(96-digit number)
21229987774094157576…62925158022680252121
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
4.245 × 10⁹⁵(96-digit number)
42459975548188315152…25850316045360504241
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
8.491 × 10⁹⁵(96-digit number)
84919951096376630304…51700632090721008481
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
1.698 × 10⁹⁶(97-digit number)
16983990219275326060…03401264181442016961
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
3.396 × 10⁹⁶(97-digit number)
33967980438550652121…06802528362884033921
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
6.793 × 10⁹⁶(97-digit number)
67935960877101304243…13605056725768067841
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
1.358 × 10⁹⁷(98-digit number)
13587192175420260848…27210113451536135681
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
2.717 × 10⁹⁷(98-digit number)
27174384350840521697…54420226903072271361
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
5.434 × 10⁹⁷(98-digit number)
54348768701681043394…08840453806144542721
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:57,732,560 XPM·at block #6,811,056 · updates every 60s
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