Block #53,754

1CCLength 8★☆☆☆☆

Cunningham Chain of the First Kind · Discovered 7/16/2013, 4:52:18 PM · Difficulty 8.9269 · 6,751,947 confirmations

1CC
Cunningham Chain of the First Kind

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

Block Header
Block Hash
9759bef3993641824a1a886c5f61b0573885e1a5222a6670f90733288d76285d

Height

#53,754

Difficulty

8.926865

Transactions

1

Size

199 B

Version

2

Bits

08ed4704

Nonce

639

Timestamp

7/16/2013, 4:52:18 PM

Confirmations

6,751,947

Merkle Root

30109699b59028feb67ed3cd1e5d662a56e022f49ad42fabaedfc2ed5922b9d4
Transactions (1)
1 in → 1 out12.5300 XPM110 B
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.

6.562 × 10⁹¹(92-digit number)
65625665833556902023…83861197898011891549
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
6.562 × 10⁹¹(92-digit number)
65625665833556902023…83861197898011891549
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
2
2^1 × origin − 1
1.312 × 10⁹²(93-digit number)
13125133166711380404…67722395796023783099
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
3
2^2 × origin − 1
2.625 × 10⁹²(93-digit number)
26250266333422760809…35444791592047566199
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
4
2^3 × origin − 1
5.250 × 10⁹²(93-digit number)
52500532666845521619…70889583184095132399
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
5
2^4 × origin − 1
1.050 × 10⁹³(94-digit number)
10500106533369104323…41779166368190264799
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
6
2^5 × origin − 1
2.100 × 10⁹³(94-digit number)
21000213066738208647…83558332736380529599
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
7
2^6 × origin − 1
4.200 × 10⁹³(94-digit number)
42000426133476417295…67116665472761059199
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
8
2^7 × origin − 1
8.400 × 10⁹³(94-digit number)
84000852266952834590…34233330945522118399
Verify on FactorDB ↗Wolfram Alpha ↗

What this block proved

The miner who found this block proved the existence of 8 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
CommonChain length 8

Found in most blocks. The baseline for Primecoin's proof-of-work.

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:57,689,689 XPM·at block #6,805,700 · updates every 60s
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