Block #319,703

1CCLength 10★★☆☆☆

Cunningham Chain of the First Kind · Discovered 12/19/2013, 4:54:30 AM · Difficulty 10.1708 · 6,505,123 confirmations

1CC
Cunningham Chain of the First Kind

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

Block Header
Block Hash
78d0232dbc72042b7a31210f1e7ae5235e97c115cc3ee5666d51dbcb3db51c7f

Height

#319,703

Difficulty

10.170829

Transactions

9

Size

15.99 KB

Version

2

Bits

0a2bbb7b

Nonce

118,967

Timestamp

12/19/2013, 4:54:30 AM

Confirmations

6,505,123

Merkle Root

a974942141c32a9e24b8067a254f94c3ced3a017afecb55ec910b884091ee9d0
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.

5.310 × 10¹⁰³(104-digit number)
53100997722866302958…57813769366134707199
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
5.310 × 10¹⁰³(104-digit number)
53100997722866302958…57813769366134707199
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
2
2^1 × origin − 1
1.062 × 10¹⁰⁴(105-digit number)
10620199544573260591…15627538732269414399
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
3
2^2 × origin − 1
2.124 × 10¹⁰⁴(105-digit number)
21240399089146521183…31255077464538828799
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
4
2^3 × origin − 1
4.248 × 10¹⁰⁴(105-digit number)
42480798178293042366…62510154929077657599
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
5
2^4 × origin − 1
8.496 × 10¹⁰⁴(105-digit number)
84961596356586084733…25020309858155315199
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
6
2^5 × origin − 1
1.699 × 10¹⁰⁵(106-digit number)
16992319271317216946…50040619716310630399
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
7
2^6 × origin − 1
3.398 × 10¹⁰⁵(106-digit number)
33984638542634433893…00081239432621260799
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
8
2^7 × origin − 1
6.796 × 10¹⁰⁵(106-digit number)
67969277085268867786…00162478865242521599
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
9
2^8 × origin − 1
1.359 × 10¹⁰⁶(107-digit number)
13593855417053773557…00324957730485043199
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
10
2^9 × origin − 1
2.718 × 10¹⁰⁶(107-digit number)
27187710834107547114…00649915460970086399
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:57,842,687 XPM·at block #6,824,825 · updates every 60s
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