Block #321,954

1CCLength 10★★☆☆☆

Cunningham Chain of the First Kind · Discovered 12/20/2013, 3:46:17 PM · Difficulty 10.1974 · 6,480,636 confirmations

1CC
Cunningham Chain of the First Kind

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

Block Header
Block Hash
f1f2594adf5428bf61dcfc060c198942abb7b8281c1d259617ccbb01f2d36e1f

Height

#321,954

Difficulty

10.197423

Transactions

7

Size

4.14 KB

Version

2

Bits

0a328a57

Nonce

4,854

Timestamp

12/20/2013, 3:46:17 PM

Confirmations

6,480,636

Merkle Root

b8f1a0f844e9b2a135a41a699262543ee55baade222ff01d980a7738b498c3d3
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.

1.462 × 10¹⁰²(103-digit number)
14625348915191835037…13176106848560261119
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
1.462 × 10¹⁰²(103-digit number)
14625348915191835037…13176106848560261119
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
2
2^1 × origin − 1
2.925 × 10¹⁰²(103-digit number)
29250697830383670075…26352213697120522239
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
3
2^2 × origin − 1
5.850 × 10¹⁰²(103-digit number)
58501395660767340151…52704427394241044479
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
4
2^3 × origin − 1
1.170 × 10¹⁰³(104-digit number)
11700279132153468030…05408854788482088959
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
5
2^4 × origin − 1
2.340 × 10¹⁰³(104-digit number)
23400558264306936060…10817709576964177919
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
6
2^5 × origin − 1
4.680 × 10¹⁰³(104-digit number)
46801116528613872120…21635419153928355839
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
7
2^6 × origin − 1
9.360 × 10¹⁰³(104-digit number)
93602233057227744241…43270838307856711679
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
8
2^7 × origin − 1
1.872 × 10¹⁰⁴(105-digit number)
18720446611445548848…86541676615713423359
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
9
2^8 × origin − 1
3.744 × 10¹⁰⁴(105-digit number)
37440893222891097696…73083353231426846719
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
10
2^9 × origin − 1
7.488 × 10¹⁰⁴(105-digit number)
74881786445782195393…46166706462853693439
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 First 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 1CC formula:

1CC: p₁ (first prime), p₂ = 2p₁ + 1, p₃ = 2p₂ + 1, …
Circulating Supply:57,664,738 XPM·at block #6,802,589 · updates every 60s
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