Block #58,783

2CCLength 8★☆☆☆☆

Cunningham Chain of the Second Kind · Discovered 7/17/2013, 10:38:57 PM · Difficulty 8.9617 · 6,731,273 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
ef8df594beaf477cb3f4adc85a69ea56312d6bc3ded3bac37a628d15112522a6

Height

#58,783

Difficulty

8.961684

Transactions

7

Size

3.51 KB

Version

2

Bits

08f630f3

Nonce

503

Timestamp

7/17/2013, 10:38:57 PM

Confirmations

6,731,273

Merkle Root

8dc5aba1ebc54a14e13943eb9352069bdf118276d15cb3443374cd7765822ab3
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.

4.690 × 10⁹³(94-digit number)
46900396112385358151…47196842439313982351
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
4.690 × 10⁹³(94-digit number)
46900396112385358151…47196842439313982351
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
9.380 × 10⁹³(94-digit number)
93800792224770716302…94393684878627964701
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
1.876 × 10⁹⁴(95-digit number)
18760158444954143260…88787369757255929401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
3.752 × 10⁹⁴(95-digit number)
37520316889908286520…77574739514511858801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
7.504 × 10⁹⁴(95-digit number)
75040633779816573041…55149479029023717601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
1.500 × 10⁹⁵(96-digit number)
15008126755963314608…10298958058047435201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
3.001 × 10⁹⁵(96-digit number)
30016253511926629216…20597916116094870401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
6.003 × 10⁹⁵(96-digit number)
60032507023853258433…41195832232189740801
Verify on FactorDB ↗Wolfram Alpha ↗

What this block proved

The miner who found this block proved the existence of 8 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
CommonChain length 8

Found in most blocks. The baseline for Primecoin's proof-of-work.

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:57,564,421 XPM·at block #6,790,055 · updates every 60s