Block #272,582

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 11/25/2013, 8:21:56 AM · Difficulty 9.9531 · 6,523,367 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
469c42064821544b28e66820e2104fd0ef4c8300dc1c8a59c96c22226314145f

Height

#272,582

Difficulty

9.953111

Transactions

9

Size

2.14 KB

Version

2

Bits

09f3ff19

Nonce

32,186

Timestamp

11/25/2013, 8:21:56 AM

Confirmations

6,523,367

Merkle Root

b4b7b1642bb955448faeb6dbf626cb5a6143d7282ac61237f78858c5fb3768a4
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.

1.428 × 10¹⁰⁴(105-digit number)
14286602157629446794…13798289917574989761
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
1.428 × 10¹⁰⁴(105-digit number)
14286602157629446794…13798289917574989761
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
2.857 × 10¹⁰⁴(105-digit number)
28573204315258893588…27596579835149979521
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
5.714 × 10¹⁰⁴(105-digit number)
57146408630517787177…55193159670299959041
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
1.142 × 10¹⁰⁵(106-digit number)
11429281726103557435…10386319340599918081
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
2.285 × 10¹⁰⁵(106-digit number)
22858563452207114870…20772638681199836161
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
4.571 × 10¹⁰⁵(106-digit number)
45717126904414229741…41545277362399672321
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
9.143 × 10¹⁰⁵(106-digit number)
91434253808828459483…83090554724799344641
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
1.828 × 10¹⁰⁶(107-digit number)
18286850761765691896…66181109449598689281
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
3.657 × 10¹⁰⁶(107-digit number)
36573701523531383793…32362218899197378561
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
7.314 × 10¹⁰⁶(107-digit number)
73147403047062767586…64724437798394757121
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:57,611,681 XPM·at block #6,795,948 · updates every 60s
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