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Home/Chain Registry/Block #1,990,455

Block #1,990,455

1CCLength 10β˜…β˜…β˜†β˜†β˜†

Cunningham Chain of the First Kind Β· Discovered 2/19/2017, 8:38:05 PM Β· Difficulty 10.7351 Β· 4,851,683 confirmations

1CC
Cunningham Chain of the First Kind

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

Block Header
Block Hash
11ddb22153c0f33b98df74d14ea7c10763bb9ce50a9397ed1b8dc8335219a10e
View on Chainz β†—

Difficulty

10.735099

Transactions

1

Size

200 B

Version

2

Bits

0abc2f6b

Nonce

922,245,538

Timestamp

2/19/2017, 8:38:05 PM

Confirmations

4,851,683

Merkle Root

bd5f3196a907c4f13aaac62e8ac10d29c95348ec0195bb3e423c408c22e3cdd7
Transactions (1)
Coinbasebd5f3196a907c4…3c408c22e3cdd7
1 in β†’ 1 out8.6600 XPM110 B
AZNuUPuK…WhxwkY4i
Prime Chain Origin

This is the prime chain origin stored in the block header. It is a composite number (not prime itself) β€” it equals the first prime in the chain multiplied by a primorial. The origin anchors the entire chain to this specific block.

5.105 Γ— 10⁹³(94-digit number)
51057857584796361787…00508436435537670040
Discovered Prime Numbers
p_k = 2^k Γ— origin βˆ’ 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 βˆ’ 1
5.105 Γ— 10⁹³(94-digit number)
51057857584796361787…00508436435537670039
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2+1 β†’
2
2^1 Γ— origin βˆ’ 1
1.021 Γ— 10⁹⁴(95-digit number)
10211571516959272357…01016872871075340079
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2+1 β†’
3
2^2 Γ— origin βˆ’ 1
2.042 Γ— 10⁹⁴(95-digit number)
20423143033918544715…02033745742150680159
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2+1 β†’
4
2^3 Γ— origin βˆ’ 1
4.084 Γ— 10⁹⁴(95-digit number)
40846286067837089430…04067491484301360319
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2+1 β†’
5
2^4 Γ— origin βˆ’ 1
8.169 Γ— 10⁹⁴(95-digit number)
81692572135674178860…08134982968602720639
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2+1 β†’
6
2^5 Γ— origin βˆ’ 1
1.633 Γ— 10⁹⁡(96-digit number)
16338514427134835772…16269965937205441279
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2+1 β†’
7
2^6 Γ— origin βˆ’ 1
3.267 Γ— 10⁹⁡(96-digit number)
32677028854269671544…32539931874410882559
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2+1 β†’
8
2^7 Γ— origin βˆ’ 1
6.535 Γ— 10⁹⁡(96-digit number)
65354057708539343088…65079863748821765119
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2+1 β†’
9
2^8 Γ— origin βˆ’ 1
1.307 Γ— 10⁹⁢(97-digit number)
13070811541707868617…30159727497643530239
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2+1 β†’
10
2^9 Γ— origin βˆ’ 1
2.614 Γ— 10⁹⁢(97-digit number)
26141623083415737235…60319454995287060479
Verify on FactorDB β†—Wolfram Alpha β†—

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 β€” the large number shown above β€” 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 β†’
β˜…β˜…β˜†β˜†β˜†
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 Γ— 3 Γ— 5 Γ— 7 Γ— …), the result is the first prime in the chain. The origin is deliberately divisible by this primorial β€” that divisibility is part of the proof.

Prime Chain Origin = First Prime Γ— Primorial (2Β·3Β·5Β·7Β·11·…)
Source: Primecoin prime.cpp β€” CheckPrimeProofOfWork()

This is why the origin has many small prime factors β€” those factors are the primorial divisor. The chain then extends from the first prime using the 1CC formula:

1CC: p₁ (first prime), pβ‚‚ = 2p₁ + 1, p₃ = 2pβ‚‚ + 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 1990455

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 11ddb22153c0f33b98df74d14ea7c10763bb9ce50a9397ed1b8dc8335219a10e

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 β†’ Debug Window β†’ 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 #1,990,455 on Chainz β†—
Circulating Supply:57,981,494 XPMΒ·at block #6,842,137 Β· updates every 60s
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