Block #479,647

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 4/7/2014, 7:37:46 PM · Difficulty 10.5098 · 6,319,792 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
f84daf0340d3e02b3f9ba08b83b11c0f6ed36921789e1c35f3be0680e899b72a

Height

#479,647

Difficulty

10.509808

Transactions

8

Size

6.63 KB

Version

2

Bits

0a8282c2

Nonce

89,340

Timestamp

4/7/2014, 7:37:46 PM

Confirmations

6,319,792

Merkle Root

15b15ed846cdbeff8817380e8aa87e8bc6a4dd0530e2473717221284020e3713
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.

1.432 × 10⁹⁵(96-digit number)
14328493143312813505…32861664843417872641
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
1.432 × 10⁹⁵(96-digit number)
14328493143312813505…32861664843417872641
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
2.865 × 10⁹⁵(96-digit number)
28656986286625627011…65723329686835745281
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
5.731 × 10⁹⁵(96-digit number)
57313972573251254022…31446659373671490561
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
1.146 × 10⁹⁶(97-digit number)
11462794514650250804…62893318747342981121
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
2.292 × 10⁹⁶(97-digit number)
22925589029300501608…25786637494685962241
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
4.585 × 10⁹⁶(97-digit number)
45851178058601003217…51573274989371924481
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
9.170 × 10⁹⁶(97-digit number)
91702356117202006435…03146549978743848961
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
1.834 × 10⁹⁷(98-digit number)
18340471223440401287…06293099957487697921
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
3.668 × 10⁹⁷(98-digit number)
36680942446880802574…12586199914975395841
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
7.336 × 10⁹⁷(98-digit number)
73361884893761605148…25172399829950791681
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:57,639,563 XPM·at block #6,799,438 · updates every 60s
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