Block #275,255

1CCLength 9★☆☆☆☆

Cunningham Chain of the First Kind · Discovered 11/26/2013, 3:10:18 PM · Difficulty 9.9603 · 6,520,710 confirmations

1CC
Cunningham Chain of the First Kind

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

Block Header
Block Hash
95e5ca15a9e67c918d979e2adf3824a1e63f07d54bb85caf7353efb031e492ac

Height

#275,255

Difficulty

9.960258

Transactions

7

Size

25.84 KB

Version

2

Bits

09f5d380

Nonce

2,383

Timestamp

11/26/2013, 3:10:18 PM

Confirmations

6,520,710

Merkle Root

7a2795fdffa65032b15d57bdc74b9eb570b8ae1ff43517627fa8f50bd3bb427a
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.

9.275 × 10¹⁰²(103-digit number)
92757086877636658423…24720511241144874599
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
9.275 × 10¹⁰²(103-digit number)
92757086877636658423…24720511241144874599
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
2
2^1 × origin − 1
1.855 × 10¹⁰³(104-digit number)
18551417375527331684…49441022482289749199
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
3
2^2 × origin − 1
3.710 × 10¹⁰³(104-digit number)
37102834751054663369…98882044964579498399
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
4
2^3 × origin − 1
7.420 × 10¹⁰³(104-digit number)
74205669502109326738…97764089929158996799
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
5
2^4 × origin − 1
1.484 × 10¹⁰⁴(105-digit number)
14841133900421865347…95528179858317993599
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
6
2^5 × origin − 1
2.968 × 10¹⁰⁴(105-digit number)
29682267800843730695…91056359716635987199
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
7
2^6 × origin − 1
5.936 × 10¹⁰⁴(105-digit number)
59364535601687461391…82112719433271974399
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
8
2^7 × origin − 1
1.187 × 10¹⁰⁵(106-digit number)
11872907120337492278…64225438866543948799
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
9
2^8 × origin − 1
2.374 × 10¹⁰⁵(106-digit number)
23745814240674984556…28450877733087897599
Verify on FactorDB ↗Wolfram Alpha ↗

What this block proved

The miner who found this block proved the existence of 9 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 9

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:57,611,811 XPM·at block #6,795,964 · updates every 60s
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