Block #2,455,542

1CCLength 11★★★☆☆

Cunningham Chain of the First Kind · Discovered 1/3/2018, 10:07:33 AM · Difficulty 10.9529 · 4,384,796 confirmations

1CC
Cunningham Chain of the First Kind

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

Block Header
Block Hash
2efd4083d53ab4556be6fa9acfd19b90b821c9562dcfeee4fe53fbf01b9e09f2

Height

#2,455,542

Difficulty

10.952884

Transactions

2

Size

2.01 KB

Version

2

Bits

0af3f03d

Nonce

833,291,046

Timestamp

1/3/2018, 10:07:33 AM

Confirmations

4,384,796

Merkle Root

67eb29e42872d120f9805b28bb508fd0266a74e137bf16dac6f3e16eb2ebfa9e
Transactions (2)
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.

3.850 × 10⁹³(94-digit number)
38509862464728566529…40073638441981946879
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
3.850 × 10⁹³(94-digit number)
38509862464728566529…40073638441981946879
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
2
2^1 × origin − 1
7.701 × 10⁹³(94-digit number)
77019724929457133059…80147276883963893759
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
3
2^2 × origin − 1
1.540 × 10⁹⁴(95-digit number)
15403944985891426611…60294553767927787519
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
4
2^3 × origin − 1
3.080 × 10⁹⁴(95-digit number)
30807889971782853223…20589107535855575039
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
5
2^4 × origin − 1
6.161 × 10⁹⁴(95-digit number)
61615779943565706447…41178215071711150079
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
6
2^5 × origin − 1
1.232 × 10⁹⁵(96-digit number)
12323155988713141289…82356430143422300159
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
7
2^6 × origin − 1
2.464 × 10⁹⁵(96-digit number)
24646311977426282579…64712860286844600319
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
8
2^7 × origin − 1
4.929 × 10⁹⁵(96-digit number)
49292623954852565158…29425720573689200639
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
9
2^8 × origin − 1
9.858 × 10⁹⁵(96-digit number)
98585247909705130316…58851441147378401279
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
10
2^9 × origin − 1
1.971 × 10⁹⁶(97-digit number)
19717049581941026063…17702882294756802559
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
11
2^10 × origin − 1
3.943 × 10⁹⁶(97-digit number)
39434099163882052126…35405764589513605119
Verify on FactorDB ↗Wolfram Alpha ↗

What this block proved

The miner who found this block proved the existence of 11 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
RareChain length 11

Approximately 1 in 1,000 blocks. Noteworthy discoveries.

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:57,967,026 XPM·at block #6,840,337 · updates every 60s
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