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Home/Chain Registry/Block #1,368,446

Block #1,368,446

2CCLength 10β˜…β˜…β˜†β˜†β˜†

Cunningham Chain of the Second Kind Β· Discovered 12/13/2015, 10:56:08 PM Β· Difficulty 10.8344 Β· 5,473,534 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
8971fa7c3f3e652f93efb648a26a4732f01a94cc73580f8b97647f827131f3ff
View on Chainz β†—

Difficulty

10.834366

Transactions

1

Size

200 B

Version

2

Bits

0ad59909

Nonce

1,364,567,255

Timestamp

12/13/2015, 10:56:08 PM

Confirmations

5,473,534

Merkle Root

88d00da12405a7b298f14438b557848a08e4c9f1393ceed75d2ea2ee19f671cb
Transactions (1)
Coinbase88d00da12405a7…2ea2ee19f671cb
1 in β†’ 1 out8.5100 XPM110 B
AMgFuB3g…RzbuWEbW
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.

3.921 Γ— 10⁹⁴(95-digit number)
39212354107718820999…31431883825274371200
Discovered Prime Numbers
p_k = 2^k Γ— 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
3.921 Γ— 10⁹⁴(95-digit number)
39212354107718820999…31431883825274371201
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
2
2^1 Γ— origin + 1
7.842 Γ— 10⁹⁴(95-digit number)
78424708215437641998…62863767650548742401
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
3
2^2 Γ— origin + 1
1.568 Γ— 10⁹⁡(96-digit number)
15684941643087528399…25727535301097484801
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
4
2^3 Γ— origin + 1
3.136 Γ— 10⁹⁡(96-digit number)
31369883286175056799…51455070602194969601
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
5
2^4 Γ— origin + 1
6.273 Γ— 10⁹⁡(96-digit number)
62739766572350113598…02910141204389939201
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
6
2^5 Γ— origin + 1
1.254 Γ— 10⁹⁢(97-digit number)
12547953314470022719…05820282408779878401
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
7
2^6 Γ— origin + 1
2.509 Γ— 10⁹⁢(97-digit number)
25095906628940045439…11640564817559756801
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
8
2^7 Γ— origin + 1
5.019 Γ— 10⁹⁢(97-digit number)
50191813257880090878…23281129635119513601
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
9
2^8 Γ— origin + 1
1.003 Γ— 10⁹⁷(98-digit number)
10038362651576018175…46562259270239027201
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
10
2^9 Γ— origin + 1
2.007 Γ— 10⁹⁷(98-digit number)
20076725303152036351…93124518540478054401
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 Second 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 2CC formula:

2CC: p₁ (first prime), pβ‚‚ = 2p₁ βˆ’ 1, p₃ = 2pβ‚‚ βˆ’ 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 1368446

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 8971fa7c3f3e652f93efb648a26a4732f01a94cc73580f8b97647f827131f3ff

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 #1,368,446 on Chainz β†—
Circulating Supply:57,980,225 XPMΒ·at block #6,841,979 Β· updates every 60s
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