Block #58,995

2CCLength 8★☆☆☆☆

Cunningham Chain of the Second Kind · Discovered 7/17/2013, 11:44:18 PM · Difficulty 8.9628 · 6,736,922 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
d336ccbfa685b8ccf9d37c66a5c55055e95f7fdb4d20ddedc7cfb3c499ff6d4c

Height

#58,995

Difficulty

8.962753

Transactions

3

Size

797 B

Version

2

Bits

08f67700

Nonce

690

Timestamp

7/17/2013, 11:44:18 PM

Confirmations

6,736,922

Merkle Root

2c5f858e21e4defafe3cf75e9e1950b6e731b20e91b29f946ea0c29a2aa1457d
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.

9.971 × 10⁸⁹(90-digit number)
99712286330408389558…10729418609585191101
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
9.971 × 10⁸⁹(90-digit number)
99712286330408389558…10729418609585191101
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
1.994 × 10⁹⁰(91-digit number)
19942457266081677911…21458837219170382201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
3.988 × 10⁹⁰(91-digit number)
39884914532163355823…42917674438340764401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
7.976 × 10⁹⁰(91-digit number)
79769829064326711646…85835348876681528801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
1.595 × 10⁹¹(92-digit number)
15953965812865342329…71670697753363057601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
3.190 × 10⁹¹(92-digit number)
31907931625730684658…43341395506726115201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
6.381 × 10⁹¹(92-digit number)
63815863251461369317…86682791013452230401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
1.276 × 10⁹²(93-digit number)
12763172650292273863…73365582026904460801
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:57,611,422 XPM·at block #6,795,916 · updates every 60s
xpmprime.info is a work in progress. If you enjoy using this service you can support this project with a Primecoin donation.