Home/Chain Registry/Block #295,566

Block #295,566

1CCLength 10★★☆☆☆

Cunningham Chain of the First Kind · Discovered 12/5/2013, 12:39:01 PM · Difficulty 9.9914 · 6,531,124 confirmations

1CC
Cunningham Chain of the First Kind

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

Block Header
Block Hash
eff63ca739e12a18eae4a88fcfeafdcab11c67456ac5beb2934056185d63fa6b

Height

#295,566

Difficulty

9.991416

Transactions

32

Size

11.60 KB

Version

2

Bits

09fdcd73

Nonce

3,034

Timestamp

12/5/2013, 12:39:01 PM

Confirmations

6,531,124

Merkle Root

6427933271607276abdbfb7fffd1828b1a8bfb1407249eee7f51bf7935070654
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.

5.679 × 10⁸⁸(89-digit number)
56795311140735762516…20194371996268857280
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
5.679 × 10⁸⁸(89-digit number)
56795311140735762516…20194371996268857279
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
2
2^1 × origin − 1
1.135 × 10⁸⁹(90-digit number)
11359062228147152503…40388743992537714559
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
3
2^2 × origin − 1
2.271 × 10⁸⁹(90-digit number)
22718124456294305006…80777487985075429119
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
4
2^3 × origin − 1
4.543 × 10⁸⁹(90-digit number)
45436248912588610013…61554975970150858239
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
5
2^4 × origin − 1
9.087 × 10⁸⁹(90-digit number)
90872497825177220026…23109951940301716479
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
6
2^5 × origin − 1
1.817 × 10⁹⁰(91-digit number)
18174499565035444005…46219903880603432959
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
7
2^6 × origin − 1
3.634 × 10⁹⁰(91-digit number)
36348999130070888010…92439807761206865919
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
8
2^7 × origin − 1
7.269 × 10⁹⁰(91-digit number)
72697998260141776021…84879615522413731839
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
9
2^8 × origin − 1
1.453 × 10⁹¹(92-digit number)
14539599652028355204…69759231044827463679
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
10
2^9 × origin − 1
2.907 × 10⁹¹(92-digit number)
29079199304056710408…39518462089654927359
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 295566

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 eff63ca739e12a18eae4a88fcfeafdcab11c67456ac5beb2934056185d63fa6b

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 #295,566 on Chainz ↗
Circulating Supply:57,857,671 XPM·at block #6,826,689 · updates every 60s
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