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Home/Chain Registry/Block #1,216,816

Block #1,216,816

1CCLength 10β˜…β˜…β˜†β˜†β˜†

Cunningham Chain of the First Kind Β· Discovered 9/1/2015, 7:54:31 AM Β· Difficulty 10.7248 Β· 5,627,929 confirmations

1CC
Cunningham Chain of the First Kind

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

Block Header
Block Hash
6e2cb50eb713cce9cc51135132c90f7ec041dfda74b9b7c9b66f7b3dd349464b
View on Chainz β†—

Difficulty

10.724778

Transactions

1

Size

199 B

Version

2

Bits

0ab98b0d

Nonce

4,346,990

Timestamp

9/1/2015, 7:54:31 AM

Confirmations

5,627,929

Merkle Root

dbe6ed7854da7d91748b602d743993512814a5d13e8a26e99b15304b2df63714
Transactions (1)
Coinbasedbe6ed7854da7d…15304b2df63714
1 in β†’ 1 out8.6800 XPM109 B
AVhpeRpG…NgZSxBeZ
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.

7.516 Γ— 10⁹⁡(96-digit number)
75161583165971552776…99522909888304350080
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
7.516 Γ— 10⁹⁡(96-digit number)
75161583165971552776…99522909888304350079
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2+1 β†’
2
2^1 Γ— origin βˆ’ 1
1.503 Γ— 10⁹⁢(97-digit number)
15032316633194310555…99045819776608700159
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2+1 β†’
3
2^2 Γ— origin βˆ’ 1
3.006 Γ— 10⁹⁢(97-digit number)
30064633266388621110…98091639553217400319
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2+1 β†’
4
2^3 Γ— origin βˆ’ 1
6.012 Γ— 10⁹⁢(97-digit number)
60129266532777242221…96183279106434800639
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2+1 β†’
5
2^4 Γ— origin βˆ’ 1
1.202 Γ— 10⁹⁷(98-digit number)
12025853306555448444…92366558212869601279
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2+1 β†’
6
2^5 Γ— origin βˆ’ 1
2.405 Γ— 10⁹⁷(98-digit number)
24051706613110896888…84733116425739202559
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2+1 β†’
7
2^6 Γ— origin βˆ’ 1
4.810 Γ— 10⁹⁷(98-digit number)
48103413226221793776…69466232851478405119
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2+1 β†’
8
2^7 Γ— origin βˆ’ 1
9.620 Γ— 10⁹⁷(98-digit number)
96206826452443587553…38932465702956810239
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2+1 β†’
9
2^8 Γ— origin βˆ’ 1
1.924 Γ— 10⁹⁸(99-digit number)
19241365290488717510…77864931405913620479
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2+1 β†’
10
2^9 Γ— origin βˆ’ 1
3.848 Γ— 10⁹⁸(99-digit number)
38482730580977435021…55729862811827240959
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 1216816

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 6e2cb50eb713cce9cc51135132c90f7ec041dfda74b9b7c9b66f7b3dd349464b

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 #1,216,816 on Chainz β†—
Circulating Supply:58,002,373 XPMΒ·at block #6,844,744 Β· updates every 60s
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