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Home/Chain Registry/Block #989,917

Block #989,917

1CCLength 10β˜…β˜…β˜†β˜†β˜†

Cunningham Chain of the First Kind Β· Discovered 3/25/2015, 9:14:10 AM Β· Difficulty 10.8521 Β· 5,806,183 confirmations

1CC
Cunningham Chain of the First Kind

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

Block Header
Block Hash
221993a275e438991c5ca980ea08e6f55dcc6b028193dc52c2c964bbbc5a74ec
View on Chainz β†—

Height

#989,917

Difficulty

10.852085

Transactions

2

Size

581 B

Version

2

Bits

0ada223d

Nonce

1,071,960,141

Timestamp

3/25/2015, 9:14:10 AM

Confirmations

5,806,183

Merkle Root

02eea17f004679a740550dd291a9190b55137baa4bbdaa3479c7cf0038322d77
Transactions (2)
Coinbase6b20f015b2418e…4fc3b9ad92580e
1 in β†’ 1 out8.4900 XPM116 B
ANSXnLY2…Sd25TjkD
402273346f27eb…30565705ee89f6
2 in β†’ 2 out16.3825 XPM374 B
AHvAYTqv…AFXT4zndATo8D213…FnUe2HYb
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.

9.038 Γ— 10⁹⁡(96-digit number)
90380367418618591610…87941540991035360320
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
9.038 Γ— 10⁹⁡(96-digit number)
90380367418618591610…87941540991035360319
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2+1 β†’
2
2^1 Γ— origin βˆ’ 1
1.807 Γ— 10⁹⁢(97-digit number)
18076073483723718322…75883081982070720639
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2+1 β†’
3
2^2 Γ— origin βˆ’ 1
3.615 Γ— 10⁹⁢(97-digit number)
36152146967447436644…51766163964141441279
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2+1 β†’
4
2^3 Γ— origin βˆ’ 1
7.230 Γ— 10⁹⁢(97-digit number)
72304293934894873288…03532327928282882559
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2+1 β†’
5
2^4 Γ— origin βˆ’ 1
1.446 Γ— 10⁹⁷(98-digit number)
14460858786978974657…07064655856565765119
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2+1 β†’
6
2^5 Γ— origin βˆ’ 1
2.892 Γ— 10⁹⁷(98-digit number)
28921717573957949315…14129311713131530239
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2+1 β†’
7
2^6 Γ— origin βˆ’ 1
5.784 Γ— 10⁹⁷(98-digit number)
57843435147915898630…28258623426263060479
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2+1 β†’
8
2^7 Γ— origin βˆ’ 1
1.156 Γ— 10⁹⁸(99-digit number)
11568687029583179726…56517246852526120959
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2+1 β†’
9
2^8 Γ— origin βˆ’ 1
2.313 Γ— 10⁹⁸(99-digit number)
23137374059166359452…13034493705052241919
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2+1 β†’
10
2^9 Γ— origin βˆ’ 1
4.627 Γ— 10⁹⁸(99-digit number)
46274748118332718904…26068987410104483839
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 989917

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 221993a275e438991c5ca980ea08e6f55dcc6b028193dc52c2c964bbbc5a74ec

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 #989,917 on Chainz β†—
Circulating Supply:57,612,793 XPMΒ·at block #6,796,099 Β· updates every 60s
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