Block #377,619

2CCLength 10ā˜…ā˜…ā˜†ā˜†ā˜†

Cunningham Chain of the Second Kind Ā· Discovered 1/27/2014, 6:34:57 AM Ā· Difficulty 10.4184 Ā· 6,425,725 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
b7534042e504fbd3a3e08faac9ce5b6133eef6afbb05d83d31885e8b2d247bc0

Height

#377,619

Difficulty

10.418353

Transactions

3

Size

805 B

Version

2

Bits

0a6b192b

Nonce

134,139

Timestamp

1/27/2014, 6:34:57 AM

Confirmations

6,425,725

Mined by

Merkle Root

5a4c58b9be75809f28070a1d8672555553d8b70e434f6b4780e16a96df83c4dd
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.

7.016 Ɨ 10¹⁰³(104-digit number)
70163193134443334781…44836249610599283201
Discovered Prime Numbers
p_k = 2^k Ɨ 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
7.016 Ɨ 10¹⁰³(104-digit number)
70163193134443334781…44836249610599283201
Verify on FactorDB ↗Wolfram Alpha ↗
Ɨ2āˆ’1 →
2
2^1 Ɨ origin + 1
1.403 Ɨ 10¹⁰⁓(105-digit number)
14032638626888666956…89672499221198566401
Verify on FactorDB ↗Wolfram Alpha ↗
Ɨ2āˆ’1 →
3
2^2 Ɨ origin + 1
2.806 Ɨ 10¹⁰⁓(105-digit number)
28065277253777333912…79344998442397132801
Verify on FactorDB ↗Wolfram Alpha ↗
Ɨ2āˆ’1 →
4
2^3 Ɨ origin + 1
5.613 Ɨ 10¹⁰⁓(105-digit number)
56130554507554667825…58689996884794265601
Verify on FactorDB ↗Wolfram Alpha ↗
Ɨ2āˆ’1 →
5
2^4 Ɨ origin + 1
1.122 Ɨ 10¹⁰⁵(106-digit number)
11226110901510933565…17379993769588531201
Verify on FactorDB ↗Wolfram Alpha ↗
Ɨ2āˆ’1 →
6
2^5 Ɨ origin + 1
2.245 Ɨ 10¹⁰⁵(106-digit number)
22452221803021867130…34759987539177062401
Verify on FactorDB ↗Wolfram Alpha ↗
Ɨ2āˆ’1 →
7
2^6 Ɨ origin + 1
4.490 Ɨ 10¹⁰⁵(106-digit number)
44904443606043734260…69519975078354124801
Verify on FactorDB ↗Wolfram Alpha ↗
Ɨ2āˆ’1 →
8
2^7 Ɨ origin + 1
8.980 Ɨ 10¹⁰⁵(106-digit number)
89808887212087468520…39039950156708249601
Verify on FactorDB ↗Wolfram Alpha ↗
Ɨ2āˆ’1 →
9
2^8 Ɨ origin + 1
1.796 Ɨ 10¹⁰⁶(107-digit number)
17961777442417493704…78079900313416499201
Verify on FactorDB ↗Wolfram Alpha ↗
Ɨ2āˆ’1 →
10
2^9 Ɨ origin + 1
3.592 Ɨ 10¹⁰⁶(107-digit number)
35923554884834987408…56159800626832998401
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.

ā˜…ā˜…ā˜†ā˜†ā˜†
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 Ɨ 3 Ɨ 5 Ɨ 7 Ɨ …), 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 Ɨ Primorial (2Ā·3Ā·5Ā·7Ā·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), pā‚‚ = 2p₁ āˆ’ 1, pā‚ƒ = 2pā‚‚ āˆ’ 1, …
Circulating Supply:57,670,785 XPMĀ·at block #6,803,343 Ā· updates every 60s
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