Block #481,792

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 4/9/2014, 2:55:57 AM · Difficulty 10.5362 · 6,342,727 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
713b145df7151294372746dc8df33045609a7763b2e5de86f6782a28c8f6cbf9

Height

#481,792

Difficulty

10.536207

Transactions

4

Size

16.21 KB

Version

2

Bits

0a8944e5

Nonce

29,112

Timestamp

4/9/2014, 2:55:57 AM

Confirmations

6,342,727

Merkle Root

976e5c4c34f1fb1e3d677c1cb29ed976491e76365fb3d93378c4dc70b4b7d0a9
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.

6.462 × 10⁹⁴(95-digit number)
64620801584650714583…94557903887904171081
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
6.462 × 10⁹⁴(95-digit number)
64620801584650714583…94557903887904171081
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
1.292 × 10⁹⁵(96-digit number)
12924160316930142916…89115807775808342161
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
2.584 × 10⁹⁵(96-digit number)
25848320633860285833…78231615551616684321
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
5.169 × 10⁹⁵(96-digit number)
51696641267720571666…56463231103233368641
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
1.033 × 10⁹⁶(97-digit number)
10339328253544114333…12926462206466737281
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
2.067 × 10⁹⁶(97-digit number)
20678656507088228666…25852924412933474561
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
4.135 × 10⁹⁶(97-digit number)
41357313014176457333…51705848825866949121
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
8.271 × 10⁹⁶(97-digit number)
82714626028352914666…03411697651733898241
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
1.654 × 10⁹⁷(98-digit number)
16542925205670582933…06823395303467796481
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
3.308 × 10⁹⁷(98-digit number)
33085850411341165866…13646790606935592961
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:57,840,215 XPM·at block #6,824,518 · updates every 60s
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