Block #365,789

2CCLength 11★★★☆☆

Cunningham Chain of the Second Kind · Discovered 1/18/2014, 11:55:45 PM · Difficulty 10.4254 · 6,440,222 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
73196bd3dbc3ded9f7dbc86336f88e6a85b24c83b591b98344be288c369708e2

Height

#365,789

Difficulty

10.425434

Transactions

4

Size

1.61 KB

Version

2

Bits

0a6ce940

Nonce

33,554,820

Timestamp

1/18/2014, 11:55:45 PM

Confirmations

6,440,222

Merkle Root

6f35c77a763c0f6c8d8a50ab6980bf3a0dd90f00ab15e849ce180ba24208e220
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.

1.686 × 10⁹⁷(98-digit number)
16860863628213016585…74832161238260705281
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
1.686 × 10⁹⁷(98-digit number)
16860863628213016585…74832161238260705281
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
3.372 × 10⁹⁷(98-digit number)
33721727256426033170…49664322476521410561
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
6.744 × 10⁹⁷(98-digit number)
67443454512852066340…99328644953042821121
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
1.348 × 10⁹⁸(99-digit number)
13488690902570413268…98657289906085642241
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
2.697 × 10⁹⁸(99-digit number)
26977381805140826536…97314579812171284481
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
5.395 × 10⁹⁸(99-digit number)
53954763610281653072…94629159624342568961
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
1.079 × 10⁹⁹(100-digit number)
10790952722056330614…89258319248685137921
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
2.158 × 10⁹⁹(100-digit number)
21581905444112661228…78516638497370275841
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
4.316 × 10⁹⁹(100-digit number)
43163810888225322457…57033276994740551681
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
8.632 × 10⁹⁹(100-digit number)
86327621776450644915…14066553989481103361
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
11
2^10 × origin + 1
1.726 × 10¹⁰⁰(101-digit number)
17265524355290128983…28133107978962206721
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 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
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 2CC formula:

2CC: p₁ (first prime), p₂ = 2p₁ − 1, p₃ = 2p₂ − 1, …
Circulating Supply:57,692,166 XPM·at block #6,806,010 · updates every 60s
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