Block #383,132

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 1/31/2014, 5:37:22 AM · Difficulty 10.3976 · 6,433,213 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
9f87e97536cec9f1f74dd34fa2190f7d6e94db5c69361c8fe76eb19ce71dd965

Height

#383,132

Difficulty

10.397635

Transactions

1

Size

833 B

Version

2

Bits

0a65cb66

Nonce

166,431

Timestamp

1/31/2014, 5:37:22 AM

Confirmations

6,433,213

Merkle Root

aa12fda6344d7088237a966bad93779272f5627408253a133a84eaa34e8ed97e
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.

4.748 × 10⁹⁵(96-digit number)
47487773228072807107…51617115240263200161
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
4.748 × 10⁹⁵(96-digit number)
47487773228072807107…51617115240263200161
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
9.497 × 10⁹⁵(96-digit number)
94975546456145614214…03234230480526400321
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
1.899 × 10⁹⁶(97-digit number)
18995109291229122842…06468460961052800641
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
3.799 × 10⁹⁶(97-digit number)
37990218582458245685…12936921922105601281
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
7.598 × 10⁹⁶(97-digit number)
75980437164916491371…25873843844211202561
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
1.519 × 10⁹⁷(98-digit number)
15196087432983298274…51747687688422405121
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
3.039 × 10⁹⁷(98-digit number)
30392174865966596548…03495375376844810241
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
6.078 × 10⁹⁷(98-digit number)
60784349731933193097…06990750753689620481
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
1.215 × 10⁹⁸(99-digit number)
12156869946386638619…13981501507379240961
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
2.431 × 10⁹⁸(99-digit number)
24313739892773277239…27963003014758481921
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:57,774,884 XPM·at block #6,816,344 · updates every 60s
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