Home/Chain Registry/Block #308,552

Block #308,552

1CCLength 10★★☆☆☆

Cunningham Chain of the First Kind · Discovered 12/13/2013, 4:06:51 AM · Difficulty 9.9945 · 6,490,287 confirmations

1CC
Cunningham Chain of the First Kind

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

Block Header
Block Hash
80e11604a0f0448eb20a7945d9cfaf32f5dfc97048f687ba4626b3fa7041163b

Height

#308,552

Difficulty

9.994538

Transactions

19

Size

8.25 KB

Version

2

Bits

09fe9a0d

Nonce

72,298

Timestamp

12/13/2013, 4:06:51 AM

Confirmations

6,490,287

Merkle Root

78933c2ebdd776a9b6cf849f347396622a32c9b0a4397e3479547b3002fa6d82
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.

3.791 × 10⁹⁶(97-digit number)
37910125021837590339…54585059320209967600
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
3.791 × 10⁹⁶(97-digit number)
37910125021837590339…54585059320209967599
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
2
2^1 × origin − 1
7.582 × 10⁹⁶(97-digit number)
75820250043675180679…09170118640419935199
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
3
2^2 × origin − 1
1.516 × 10⁹⁷(98-digit number)
15164050008735036135…18340237280839870399
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
4
2^3 × origin − 1
3.032 × 10⁹⁷(98-digit number)
30328100017470072271…36680474561679740799
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
5
2^4 × origin − 1
6.065 × 10⁹⁷(98-digit number)
60656200034940144543…73360949123359481599
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
6
2^5 × origin − 1
1.213 × 10⁹⁸(99-digit number)
12131240006988028908…46721898246718963199
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
7
2^6 × origin − 1
2.426 × 10⁹⁸(99-digit number)
24262480013976057817…93443796493437926399
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
8
2^7 × origin − 1
4.852 × 10⁹⁸(99-digit number)
48524960027952115634…86887592986875852799
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
9
2^8 × origin − 1
9.704 × 10⁹⁸(99-digit number)
97049920055904231269…73775185973751705599
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
10
2^9 × origin − 1
1.940 × 10⁹⁹(100-digit number)
19409984011180846253…47550371947503411199
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 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.

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 1CC formula:

1CC: 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 308552

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 80e11604a0f0448eb20a7945d9cfaf32f5dfc97048f687ba4626b3fa7041163b

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 #308,552 on Chainz ↗
Circulating Supply:57,634,744 XPM·at block #6,798,838 · updates every 60s
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