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Block #120,455

1CCLength 10β˜…β˜…β˜†β˜†β˜†

Cunningham Chain of the First Kind Β· Discovered 8/17/2013, 4:36:35 AM Β· Difficulty 9.7499 Β· 6,693,986 confirmations

1CC
Cunningham Chain of the First Kind

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

Block Header
Block Hash
24736e49a373d6203475b7f8f2c3fca1ad3ce49ce6da9adbdc74334c6b9d61ae
View on Chainz β†—

Height

#120,455

Difficulty

9.749941

Transactions

2

Size

949 B

Version

2

Bits

09bffc1b

Nonce

46,616

Timestamp

8/17/2013, 4:36:35 AM

Confirmations

6,693,986

Merkle Root

885c1a3a4ef61bd371fe9a08fca160ccccb48023d643c061eb83b54d1843914c
Transactions (2)
Coinbase86c38c867f60e2…7e1a9e4d11169c
1 in β†’ 1 out10.5100 XPM109 B
AKaGDwVV…h5Bk5GFu
f78314e1fc1bc4…79b274e9a75497
5 in β†’ 1 out157.0400 XPM750 B
ASRtmbRb…qKKgffha
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.

1.380 Γ— 10⁹⁡(96-digit number)
13800794539528788058…22398441447703715340
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
1.380 Γ— 10⁹⁡(96-digit number)
13800794539528788058…22398441447703715339
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2+1 β†’
2
2^1 Γ— origin βˆ’ 1
2.760 Γ— 10⁹⁡(96-digit number)
27601589079057576116…44796882895407430679
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2+1 β†’
3
2^2 Γ— origin βˆ’ 1
5.520 Γ— 10⁹⁡(96-digit number)
55203178158115152233…89593765790814861359
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2+1 β†’
4
2^3 Γ— origin βˆ’ 1
1.104 Γ— 10⁹⁢(97-digit number)
11040635631623030446…79187531581629722719
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2+1 β†’
5
2^4 Γ— origin βˆ’ 1
2.208 Γ— 10⁹⁢(97-digit number)
22081271263246060893…58375063163259445439
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2+1 β†’
6
2^5 Γ— origin βˆ’ 1
4.416 Γ— 10⁹⁢(97-digit number)
44162542526492121786…16750126326518890879
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2+1 β†’
7
2^6 Γ— origin βˆ’ 1
8.832 Γ— 10⁹⁢(97-digit number)
88325085052984243573…33500252653037781759
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2+1 β†’
8
2^7 Γ— origin βˆ’ 1
1.766 Γ— 10⁹⁷(98-digit number)
17665017010596848714…67000505306075563519
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2+1 β†’
9
2^8 Γ— origin βˆ’ 1
3.533 Γ— 10⁹⁷(98-digit number)
35330034021193697429…34001010612151127039
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2+1 β†’
10
2^9 Γ— origin βˆ’ 1
7.066 Γ— 10⁹⁷(98-digit number)
70660068042387394858…68002021224302254079
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 120455

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 24736e49a373d6203475b7f8f2c3fca1ad3ce49ce6da9adbdc74334c6b9d61ae

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 #120,455 on Chainz β†—
Circulating Supply:57,759,597 XPMΒ·at block #6,814,440 Β· updates every 60s
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