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Block #60,605

2CCLength 8β˜…β˜†β˜†β˜†β˜†

Cunningham Chain of the Second Kind Β· Discovered 7/18/2013, 8:53:05 AM Β· Difficulty 8.9699 Β· 6,765,441 confirmations

2CC
Cunningham Chain of the Second Kind

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

Block Header
Block Hash
a73fdc1f469abb63e4a61076298f259fc23b1c01b6591c255546a3b9d4ad5e40
View on Chainz β†—

Height

#60,605

Difficulty

8.969896

Transactions

1

Size

202 B

Version

2

Bits

08f84b1d

Nonce

76

Timestamp

7/18/2013, 8:53:05 AM

Confirmations

6,765,441

Merkle Root

452c958e297c83e562ba908914f3f9099d225ee7e57a75a84be79b75969ee6de
Transactions (1)
Coinbase452c958e297c83…e79b75969ee6de
1 in β†’ 1 out12.4100 XPM109 B
AUUvVjdW…9CVhFSpA
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.

1.945 Γ— 10¹⁰²(103-digit number)
19451676760340455184…06314411494228880990
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
1.945 Γ— 10¹⁰²(103-digit number)
19451676760340455184…06314411494228880991
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
2
2^1 Γ— origin + 1
3.890 Γ— 10¹⁰²(103-digit number)
38903353520680910369…12628822988457761981
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
3
2^2 Γ— origin + 1
7.780 Γ— 10¹⁰²(103-digit number)
77806707041361820739…25257645976915523961
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
4
2^3 Γ— origin + 1
1.556 Γ— 10¹⁰³(104-digit number)
15561341408272364147…50515291953831047921
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
5
2^4 Γ— origin + 1
3.112 Γ— 10¹⁰³(104-digit number)
31122682816544728295…01030583907662095841
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
6
2^5 Γ— origin + 1
6.224 Γ— 10¹⁰³(104-digit number)
62245365633089456591…02061167815324191681
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
7
2^6 Γ— origin + 1
1.244 Γ— 10¹⁰⁴(105-digit number)
12449073126617891318…04122335630648383361
Verify on FactorDB β†—Wolfram Alpha β†—
Γ—2βˆ’1 β†’
8
2^7 Γ— origin + 1
2.489 Γ— 10¹⁰⁴(105-digit number)
24898146253235782636…08244671261296766721
Verify on FactorDB β†—Wolfram Alpha β†—

What this block proved

The miner who found this block proved the existence of 8 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
CommonChain length 8
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 60605

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 a73fdc1f469abb63e4a61076298f259fc23b1c01b6591c255546a3b9d4ad5e40

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 #60,605 on Chainz β†—
Circulating Supply:57,852,494 XPMΒ·at block #6,826,045 Β· updates every 60s
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