Home/Chain Registry/Block #276,660

Block #276,660

1CCLength 9★☆☆☆☆

Cunningham Chain of the First Kind · Discovered 11/27/2013, 6:48:41 AM · Difficulty 9.9638 · 6,513,342 confirmations

1CC
Cunningham Chain of the First Kind

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

Block Header
Block Hash
ad67c0e9193dc95648f9131238cc0008ce375edcfbdb19ec9f4a5f552c51263b

Height

#276,660

Difficulty

9.963827

Transactions

10

Size

222.89 KB

Version

2

Bits

09f6bd58

Nonce

70,924

Timestamp

11/27/2013, 6:48:41 AM

Confirmations

6,513,342

Merkle Root

07f45d04883fe33e149d9fabb197ce1adb3088d12cc11d406cd4db3c4e9d4cbc
Prime Chain Origin

This is the prime chain origin stored in the block header. It is a composite number (not prime itself) — it equals the first prime in the chain multiplied by a primorial. The origin anchors the entire chain to this specific block.

4.625 × 10⁹⁶(97-digit number)
46258951588431017956…11608535573142592000
Discovered Prime Numbers
p_k = 2^k × 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
4.625 × 10⁹⁶(97-digit number)
46258951588431017956…11608535573142591999
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
2
2^1 × origin − 1
9.251 × 10⁹⁶(97-digit number)
92517903176862035913…23217071146285183999
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
3
2^2 × origin − 1
1.850 × 10⁹⁷(98-digit number)
18503580635372407182…46434142292570367999
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
4
2^3 × origin − 1
3.700 × 10⁹⁷(98-digit number)
37007161270744814365…92868284585140735999
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
5
2^4 × origin − 1
7.401 × 10⁹⁷(98-digit number)
74014322541489628730…85736569170281471999
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
6
2^5 × origin − 1
1.480 × 10⁹⁸(99-digit number)
14802864508297925746…71473138340562943999
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
7
2^6 × origin − 1
2.960 × 10⁹⁸(99-digit number)
29605729016595851492…42946276681125887999
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
8
2^7 × origin − 1
5.921 × 10⁹⁸(99-digit number)
59211458033191702984…85892553362251775999
Verify on FactorDB ↗Wolfram Alpha ↗
×2+1 →
9
2^8 × origin − 1
1.184 × 10⁹⁹(100-digit number)
11842291606638340596…71785106724503551999
Verify on FactorDB ↗Wolfram Alpha ↗

What this block proved

The miner who found this block proved the existence of 9 consecutive prime numbers forming a Cunningham Chain of the First Kind. The prime chain origin — the large number shown above — 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 →
★☆☆☆☆
Rarity
CommonChain length 9
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 × 3 × 5 × 7 × …), the result is the first prime in the chain. The origin is deliberately divisible by this primorial — that divisibility is part of the proof.

Prime Chain Origin = First Prime × Primorial (2·3·5·7·11·…)
Source: Primecoin prime.cpp — CheckPrimeProofOfWork()

This is why the origin has many small prime factors — those factors are the primorial divisor. The chain then extends from the first prime using the 1CC formula:

1CC: p₁ (first prime), p₂ = 2p₁ + 1, p₃ = 2p₂ + 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 276660

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 ad67c0e9193dc95648f9131238cc0008ce375edcfbdb19ec9f4a5f552c51263b

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 → Debug Window → 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 #276,660 on Chainz ↗
Circulating Supply:57,563,999 XPM·at block #6,790,001 · updates every 60s