Block #2,475,122

1CCLength 11★★★☆☆

Cunningham Chain of the First Kind · Discovered 1/16/2018, 3:45:02 AM · Difficulty 10.9637 · 4,366,589 confirmations

1CC
Cunningham Chain of the First Kind

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

Block Header
Block Hash
1a50abb3f855441c072b4ad8f9b64e7ba00e0d9927d64a73a87aefc85b7026ac

Height

#2,475,122

Difficulty

10.963711

Transactions

30

Size

6.72 KB

Version

2

Bits

0af6b5cb

Nonce

937,969,754

Timestamp

1/16/2018, 3:45:02 AM

Confirmations

4,366,589

Merkle Root

dad4895ca2c768707cddbd1c85e67d0e2cb83101c356a2f18022a3cd5a84f07c
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.

5.390 × 10⁹⁴(95-digit number)
53902804570462264326…99390230911517943919
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
5.390 × 10⁹⁴(95-digit number)
53902804570462264326…99390230911517943919
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
2
2^1 × origin − 1
1.078 × 10⁹⁵(96-digit number)
10780560914092452865…98780461823035887839
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
3
2^2 × origin − 1
2.156 × 10⁹⁵(96-digit number)
21561121828184905730…97560923646071775679
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
4
2^3 × origin − 1
4.312 × 10⁹⁵(96-digit number)
43122243656369811461…95121847292143551359
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
5
2^4 × origin − 1
8.624 × 10⁹⁵(96-digit number)
86244487312739622922…90243694584287102719
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
6
2^5 × origin − 1
1.724 × 10⁹⁶(97-digit number)
17248897462547924584…80487389168574205439
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
7
2^6 × origin − 1
3.449 × 10⁹⁶(97-digit number)
34497794925095849169…60974778337148410879
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
8
2^7 × origin − 1
6.899 × 10⁹⁶(97-digit number)
68995589850191698338…21949556674296821759
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
9
2^8 × origin − 1
1.379 × 10⁹⁷(98-digit number)
13799117970038339667…43899113348593643519
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
10
2^9 × origin − 1
2.759 × 10⁹⁷(98-digit number)
27598235940076679335…87798226697187287039
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
11
2^10 × origin − 1
5.519 × 10⁹⁷(98-digit number)
55196471880153358670…75596453394374574079
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:57,978,067 XPM·at block #6,841,710 · updates every 60s
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