Home/Chain Registry/Block #369,220

Block #369,220

2CCLength 10★★☆☆☆

Cunningham Chain of the Second Kind · Discovered 1/21/2014, 6:23:44 AM · Difficulty 10.4446 · 6,421,887 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
a7dd945844c818faf08c3cbff53550b1ca0cdeb264389caa8c26c00d382879d5

Height

#369,220

Difficulty

10.444604

Transactions

18

Size

23.00 KB

Version

2

Bits

0a71d197

Nonce

130,823

Timestamp

1/21/2014, 6:23:44 AM

Confirmations

6,421,887

Merkle Root

460a35f1886364c80700b5eae71b14b594b47305c19009337c2c61ce1a409171
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.

2.926 × 10¹⁰⁰(101-digit number)
29265348730176301252…23323011753650777600
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
2.926 × 10¹⁰⁰(101-digit number)
29265348730176301252…23323011753650777601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
2
2^1 × origin + 1
5.853 × 10¹⁰⁰(101-digit number)
58530697460352602504…46646023507301555201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
3
2^2 × origin + 1
1.170 × 10¹⁰¹(102-digit number)
11706139492070520500…93292047014603110401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
4
2^3 × origin + 1
2.341 × 10¹⁰¹(102-digit number)
23412278984141041001…86584094029206220801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
5
2^4 × origin + 1
4.682 × 10¹⁰¹(102-digit number)
46824557968282082003…73168188058412441601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
6
2^5 × origin + 1
9.364 × 10¹⁰¹(102-digit number)
93649115936564164007…46336376116824883201
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
7
2^6 × origin + 1
1.872 × 10¹⁰²(103-digit number)
18729823187312832801…92672752233649766401
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
8
2^7 × origin + 1
3.745 × 10¹⁰²(103-digit number)
37459646374625665602…85345504467299532801
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
9
2^8 × origin + 1
7.491 × 10¹⁰²(103-digit number)
74919292749251331205…70691008934599065601
Verify on FactorDB ↗Wolfram Alpha ↗
×2−1 →
10
2^9 × origin + 1
1.498 × 10¹⁰³(104-digit number)
14983858549850266241…41382017869198131201
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.

View full Prime Chain Discovery page →
★★☆☆☆
Rarity
UncommonChain length 10
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, …
Verify on a Primecoin Node

Anyone running a Primecoin node can independently verify this block using the following RPC commands. Run these from the primecoin-cli command line or via the debug console in the Primecoin wallet.

1. Get block hash by height
getblockhash 369220

Returns the block hash for a given block height. Use this to confirm the hash shown above matches the chain.

2. Get full block data
getblock a7dd945844c818faf08c3cbff53550b1ca0cdeb264389caa8c26c00d382879d5

Returns the full block header including difficulty, prime chain origin, prime chain type, transaction IDs, and all other fields shown on this page.

How to run these commands: To verify this data independently, open a terminal on your own Primecoin node and run primecoin-cli <command>. Alternatively, open the Primecoin-Qt wallet, go to Help → Debug Window → Console, and type the command directly. The node must be fully synced to this block height for the commands to return results.

Cross-reference on Chainz Explorer

Chainz is an independent Primecoin block explorer. Compare this block's data to verify accuracy.

View Block #369,220 on Chainz ↗
Circulating Supply:57,572,788 XPM·at block #6,791,106 · updates every 60s
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