Block #310,462

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 12/14/2013, 2:11:47 AM · Difficulty 9.9952 · 6,495,968 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
cddc48c7779d3c04a12a8823f3c8e0ab0e933211649df7fcc27185532f85d7ee

Height

#310,462

Difficulty

9.995189

Transactions

16

Size

4.36 KB

Version

2

Bits

09fec4b4

Nonce

815

Timestamp

12/14/2013, 2:11:47 AM

Confirmations

6,495,968

Merkle Root

9dec17efa92a6bd5d7e51815ae813af89365903bb13c7fcdb2d03c80d0af66f2
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.

6.037 × 10⁹⁶(97-digit number)
60371500735322743404…36244051548487281401
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
6.037 × 10⁹⁶(97-digit number)
60371500735322743404…36244051548487281401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
1.207 × 10⁹⁷(98-digit number)
12074300147064548680…72488103096974562801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
2.414 × 10⁹⁷(98-digit number)
24148600294129097361…44976206193949125601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
4.829 × 10⁹⁷(98-digit number)
48297200588258194723…89952412387898251201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
9.659 × 10⁹⁷(98-digit number)
96594401176516389446…79904824775796502401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
1.931 × 10⁹⁸(99-digit number)
19318880235303277889…59809649551593004801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
3.863 × 10⁹⁸(99-digit number)
38637760470606555778…19619299103186009601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
7.727 × 10⁹⁸(99-digit number)
77275520941213111557…39238598206372019201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
1.545 × 10⁹⁹(100-digit number)
15455104188242622311…78477196412744038401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
3.091 × 10⁹⁹(100-digit number)
30910208376485244622…56954392825488076801
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:57,695,537 XPM·at block #6,806,429 · updates every 60s
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